[PATCH v2 0/9] vhost-user part 1, v6

[PATCH v2 0/9] vhost-user part 1, v6

[David Gibson]

When I rebased by own code, I hit the problems Stefano mentioned with
static checker regressions in the vhost-user series.  Laurent's most
recent vhost-user part 1 series, but with fixes applied for the
cppcheck and clang-tidy regressions introduced.

Changes since 'v5 + static checker fixes'
 * Added my own alteration notes and S-o-b
Changes since v5:
 * Fixed a number of static checker regressions

Laurent Vivier (9):
  pcap: add pcap_iov()
  checksum: align buffers
  checksum: add csum_iov()
  util: move IP stuff from util.[ch] to ip.[ch]
  udp: little cleanup in udp_update_hdrX() to prepare future changes
  checksum: use csum_ip4_header() in udp.c and tcp.c
  checksum: introduce functions to compute the header part checksum for
    TCP/UDP
  tap: make tap_update_mac() generic
  tcp: Introduce tcp_fill_headers4()/tcp_fill_headers6()

 Makefile     |  10 +--
 checksum.c   | 173 ++++++++++++++++++++++++++++++----------
 checksum.h   |  12 ++-
 conf.c       |   1 +
 dhcp.c       |   1 +
 flow.c       |   1 +
 fwd.c        |   1 +
 icmp.c       |   1 +
 inany.c      |   1 +
 iov.c        |   1 -
 ip.c         |  72 +++++++++++++++++
 ip.h         |  86 ++++++++++++++++++++
 ndp.c        |   1 +
 pcap.c       |  27 ++++++-
 pcap.h       |   1 +
 qrap.c       |   1 +
 tap.c        |  13 +--
 tap.h        |   2 +-
 tcp.c        | 221 +++++++++++++++++++++++++++++----------------------
 tcp_splice.c |   1 +
 udp.c        |  82 ++++++++-----------
 util.c       |  55 -------------
 util.h       |  76 ------------------
 23 files changed, 505 insertions(+), 335 deletions(-)
 create mode 100644 ip.c
 create mode 100644 ip.h

-- 
2.44.0

[PATCH v2 1/9] pcap: add pcap_iov()

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

Introduce a new function pcap_iov() to capture packet desribed by an IO
vector.

Update pcap_frame() to manage iovcnt > 1.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-2-lvivier@redhat.com>
[dwg: Fixed trivial cppcheck regressions]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 iov.c  |  1 -
 pcap.c | 27 +++++++++++++++++++++++----
 pcap.h |  1 +
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/iov.c b/iov.c
index e3312628..e7b4eb75 100644
--- a/iov.c
+++ b/iov.c
@@ -146,7 +146,6 @@ size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
  *
  * Returns:    The total size in bytes.
  */
-/* cppcheck-suppress unusedFunction */
 size_t iov_size(const struct iovec *iov, size_t iov_cnt)
 {
 	unsigned int i;
diff --git a/pcap.c b/pcap.c
index a4057b5f..a0f01ad3 100644
--- a/pcap.c
+++ b/pcap.c
@@ -32,6 +32,7 @@
 #include "passt.h"
 #include "log.h"
 #include "pcap.h"
+#include "iov.h"
 
 #define PCAP_VERSION_MINOR 4
 
@@ -78,7 +79,7 @@ struct pcap_pkthdr {
 static void pcap_frame(const struct iovec *iov, size_t iovcnt,
 		       size_t offset, const struct timeval *tv)
 {
-	size_t len = iov->iov_len - offset;
+	size_t len = iov_size(iov, iovcnt) - offset;
 	struct pcap_pkthdr h = {
 		.tv_sec = tv->tv_sec,
 		.tv_usec = tv->tv_usec,
@@ -87,10 +88,8 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
 	};
 	struct iovec hiov = { &h, sizeof(h) };
 
-	(void)iovcnt;
-
 	if (write_remainder(pcap_fd, &hiov, 1, 0) < 0 ||
-	    write_remainder(pcap_fd, iov, 1, offset) < 0) {
+	    write_remainder(pcap_fd, iov, iovcnt, offset) < 0) {
 		debug("Cannot log packet, length %zu: %s",
 		      len, strerror(errno));
 	}
@@ -135,6 +134,26 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 		pcap_frame(iov + i * frame_parts, frame_parts, offset, &tv);
 }
 
+/*
+ * pcap_iov - Write packet data described by an I/O vector
+ *		to a pcap file descriptor.
+ *
+ * @iov:	Pointer to the array of struct iovec describing the I/O vector
+ *		containing packet data to write, including L2 header
+ * @iovcnt:	Number of buffers (@iov entries)
+ */
+/* cppcheck-suppress unusedFunction */
+void pcap_iov(const struct iovec *iov, size_t iovcnt)
+{
+	struct timeval tv;
+
+	if (pcap_fd == -1)
+		return;
+
+	gettimeofday(&tv, NULL);
+	pcap_frame(iov, iovcnt, 0, &tv);
+}
+
 /**
  * pcap_init() - Initialise pcap file
  * @c:		Execution context
diff --git a/pcap.h b/pcap.h
index 85fc58e5..15d46572 100644
--- a/pcap.h
+++ b/pcap.h
@@ -9,6 +9,7 @@
 void pcap(const char *pkt, size_t len);
 void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 		   size_t offset);
+void pcap_iov(const struct iovec *iov, size_t iovcnt);
 void pcap_init(struct ctx *c);
 
 #endif /* PCAP_H */
-- 
@@ -9,6 +9,7 @@
 void pcap(const char *pkt, size_t len);
 void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 		   size_t offset);
+void pcap_iov(const struct iovec *iov, size_t iovcnt);
 void pcap_init(struct ctx *c);
 
 #endif /* PCAP_H */
-- 
2.44.0

[PATCH v2 2/9] checksum: align buffers

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

If buffer is not aligned use sum_16b() only on the not aligned
part, and then use csum_avx2() on the remaining part

Remove unneeded now function csum_unaligned().

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-3-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 checksum.c | 47 ++++++++++++++++++++++++-----------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/checksum.c b/checksum.c
index f21c9b7a..65486b46 100644
--- a/checksum.c
+++ b/checksum.c
@@ -56,6 +56,8 @@
 #include <linux/udp.h>
 #include <linux/icmpv6.h>
 
+#include "util.h"
+
 /* Checksums are optional for UDP over IPv4, so we usually just set
  * them to 0.  Change this to 1 to calculate real UDP over IPv4
  * checksums
@@ -110,20 +112,7 @@ uint16_t csum_fold(uint32_t sum)
 	return sum;
 }
 
-/**
- * csum_unaligned() - Compute TCP/IP-style checksum for not 32-byte aligned data
- * @buf:	Input data
- * @len:	Input length
- * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
- *
- * Return: 16-bit IPv4-style checksum
- */
-/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
-__attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
-uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init)
-{
-	return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
-}
+uint16_t csum(const void *buf, size_t len, uint32_t init);
 
 /**
  * csum_ip4_header() - Calculate and set IPv4 header checksum
@@ -132,7 +121,7 @@ uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init)
 void csum_ip4_header(struct iphdr *ip4h)
 {
 	ip4h->check = 0;
-	ip4h->check = csum_unaligned(ip4h, (size_t)ip4h->ihl * 4, 0);
+	ip4h->check = csum(ip4h, (size_t)ip4h->ihl * 4, 0);
 }
 
 /**
@@ -159,7 +148,7 @@ void csum_udp4(struct udphdr *udp4hr,
 			+ htons(IPPROTO_UDP);
 		/* Add in partial checksum for the UDP header alone */
 		psum += sum_16b(udp4hr, sizeof(*udp4hr));
-		udp4hr->check = csum_unaligned(payload, len, psum);
+		udp4hr->check = csum(payload, len, psum);
 	}
 }
 
@@ -178,7 +167,7 @@ void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len)
 	/* Partial checksum for ICMP header alone */
 	psum = sum_16b(icmp4hr, sizeof(*icmp4hr));
 
-	icmp4hr->checksum = csum_unaligned(payload, len, psum);
+	icmp4hr->checksum = csum(payload, len, psum);
 }
 
 /**
@@ -199,7 +188,7 @@ void csum_udp6(struct udphdr *udp6hr,
 	udp6hr->check = 0;
 	/* Add in partial checksum for the UDP header alone */
 	psum += sum_16b(udp6hr, sizeof(*udp6hr));
-	udp6hr->check = csum_unaligned(payload, len, psum);
+	udp6hr->check = csum(payload, len, psum);
 }
 
 /**
@@ -222,7 +211,7 @@ void csum_icmp6(struct icmp6hdr *icmp6hr,
 	icmp6hr->icmp6_cksum = 0;
 	/* Add in partial checksum for the ICMPv6 header alone */
 	psum += sum_16b(icmp6hr, sizeof(*icmp6hr));
-	icmp6hr->icmp6_cksum = csum_unaligned(payload, len, psum);
+	icmp6hr->icmp6_cksum = csum(payload, len, psum);
 }
 
 #ifdef __AVX2__
@@ -397,17 +386,29 @@ less_than_128_bytes:
 
 /**
  * csum() - Compute TCP/IP-style checksum
- * @buf:	Input buffer, must be aligned to 32-byte boundary
+ * @buf:	Input buffer
  * @len:	Input length
  * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
  *
- * Return: 16-bit folded, complemented checksum sum
+ * Return: 16-bit folded, complemented checksum
  */
 /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
 uint16_t csum(const void *buf, size_t len, uint32_t init)
 {
-	return (uint16_t)~csum_fold(csum_avx2(buf, len, init));
+	intptr_t align = ROUND_UP((intptr_t)buf, sizeof(__m256i));
+	unsigned int pad = align - (intptr_t)buf;
+
+	if (len < pad)
+		pad = len;
+
+	if (pad)
+		init += sum_16b(buf, pad);
+
+	if (len > pad)
+		init = csum_avx2((void *)align, len - pad, init);
+
+	return (uint16_t)~csum_fold(init);
 }
 
 #else /* __AVX2__ */
@@ -424,7 +425,7 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
 uint16_t csum(const void *buf, size_t len, uint32_t init)
 {
-	return csum_unaligned(buf, len, init);
+	return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
 }
 
 #endif /* !__AVX2__ */
-- 
@@ -56,6 +56,8 @@
 #include <linux/udp.h>
 #include <linux/icmpv6.h>
 
+#include "util.h"
+
 /* Checksums are optional for UDP over IPv4, so we usually just set
  * them to 0.  Change this to 1 to calculate real UDP over IPv4
  * checksums
@@ -110,20 +112,7 @@ uint16_t csum_fold(uint32_t sum)
 	return sum;
 }
 
-/**
- * csum_unaligned() - Compute TCP/IP-style checksum for not 32-byte aligned data
- * @buf:	Input data
- * @len:	Input length
- * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
- *
- * Return: 16-bit IPv4-style checksum
- */
-/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
-__attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
-uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init)
-{
-	return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
-}
+uint16_t csum(const void *buf, size_t len, uint32_t init);
 
 /**
  * csum_ip4_header() - Calculate and set IPv4 header checksum
@@ -132,7 +121,7 @@ uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init)
 void csum_ip4_header(struct iphdr *ip4h)
 {
 	ip4h->check = 0;
-	ip4h->check = csum_unaligned(ip4h, (size_t)ip4h->ihl * 4, 0);
+	ip4h->check = csum(ip4h, (size_t)ip4h->ihl * 4, 0);
 }
 
 /**
@@ -159,7 +148,7 @@ void csum_udp4(struct udphdr *udp4hr,
 			+ htons(IPPROTO_UDP);
 		/* Add in partial checksum for the UDP header alone */
 		psum += sum_16b(udp4hr, sizeof(*udp4hr));
-		udp4hr->check = csum_unaligned(payload, len, psum);
+		udp4hr->check = csum(payload, len, psum);
 	}
 }
 
@@ -178,7 +167,7 @@ void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len)
 	/* Partial checksum for ICMP header alone */
 	psum = sum_16b(icmp4hr, sizeof(*icmp4hr));
 
-	icmp4hr->checksum = csum_unaligned(payload, len, psum);
+	icmp4hr->checksum = csum(payload, len, psum);
 }
 
 /**
@@ -199,7 +188,7 @@ void csum_udp6(struct udphdr *udp6hr,
 	udp6hr->check = 0;
 	/* Add in partial checksum for the UDP header alone */
 	psum += sum_16b(udp6hr, sizeof(*udp6hr));
-	udp6hr->check = csum_unaligned(payload, len, psum);
+	udp6hr->check = csum(payload, len, psum);
 }
 
 /**
@@ -222,7 +211,7 @@ void csum_icmp6(struct icmp6hdr *icmp6hr,
 	icmp6hr->icmp6_cksum = 0;
 	/* Add in partial checksum for the ICMPv6 header alone */
 	psum += sum_16b(icmp6hr, sizeof(*icmp6hr));
-	icmp6hr->icmp6_cksum = csum_unaligned(payload, len, psum);
+	icmp6hr->icmp6_cksum = csum(payload, len, psum);
 }
 
 #ifdef __AVX2__
@@ -397,17 +386,29 @@ less_than_128_bytes:
 
 /**
  * csum() - Compute TCP/IP-style checksum
- * @buf:	Input buffer, must be aligned to 32-byte boundary
+ * @buf:	Input buffer
  * @len:	Input length
  * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
  *
- * Return: 16-bit folded, complemented checksum sum
+ * Return: 16-bit folded, complemented checksum
  */
 /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
 uint16_t csum(const void *buf, size_t len, uint32_t init)
 {
-	return (uint16_t)~csum_fold(csum_avx2(buf, len, init));
+	intptr_t align = ROUND_UP((intptr_t)buf, sizeof(__m256i));
+	unsigned int pad = align - (intptr_t)buf;
+
+	if (len < pad)
+		pad = len;
+
+	if (pad)
+		init += sum_16b(buf, pad);
+
+	if (len > pad)
+		init = csum_avx2((void *)align, len - pad, init);
+
+	return (uint16_t)~csum_fold(init);
 }
 
 #else /* __AVX2__ */
@@ -424,7 +425,7 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
 uint16_t csum(const void *buf, size_t len, uint32_t init)
 {
-	return csum_unaligned(buf, len, init);
+	return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
 }
 
 #endif /* !__AVX2__ */
-- 
2.44.0

[PATCH v2 3/9] checksum: add csum_iov()

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

Introduce the function csum_unfolded() that computes the unfolded
32-bit checksum of a data buffer, and call it from csum() that returns
the folded value.

Introduce csum_iov() that computes the checksum using csum_folded() on
all vectors of the iovec array and returns the folded result.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-4-lvivier@redhat.com>
[dwg: Fixed trivial cppcheck & clang-tidy regressions]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 checksum.c | 59 ++++++++++++++++++++++++++++++++++++++++++------------
 checksum.h |  4 +++-
 2 files changed, 49 insertions(+), 14 deletions(-)

diff --git a/checksum.c b/checksum.c
index 65486b46..643957b5 100644
--- a/checksum.c
+++ b/checksum.c
@@ -57,6 +57,7 @@
 #include <linux/icmpv6.h>
 
 #include "util.h"
+#include "checksum.h"
 
 /* Checksums are optional for UDP over IPv4, so we usually just set
  * them to 0.  Change this to 1 to calculate real UDP over IPv4
@@ -112,8 +113,6 @@ uint16_t csum_fold(uint32_t sum)
 	return sum;
 }
 
-uint16_t csum(const void *buf, size_t len, uint32_t init);
-
 /**
  * csum_ip4_header() - Calculate and set IPv4 header checksum
  * @ip4h:	IPv4 header
@@ -385,16 +384,17 @@ less_than_128_bytes:
 }
 
 /**
- * csum() - Compute TCP/IP-style checksum
- * @buf:	Input buffer
- * @len:	Input length
- * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
+ * csum_unfolded - Calculate the unfolded checksum of a data buffer.
  *
- * Return: 16-bit folded, complemented checksum
+ * @buf:   Input buffer
+ * @len:   Input length
+ * @init:  Initial 32-bit checksum, 0 for no pre-computed checksum
+ *
+ * Return: 32-bit unfolded
  */
 /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
-uint16_t csum(const void *buf, size_t len, uint32_t init)
+uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
 {
 	intptr_t align = ROUND_UP((intptr_t)buf, sizeof(__m256i));
 	unsigned int pad = align - (intptr_t)buf;
@@ -408,16 +408,31 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
 	if (len > pad)
 		init = csum_avx2((void *)align, len - pad, init);
 
-	return (uint16_t)~csum_fold(init);
+	return init;
 }
-
 #else /* __AVX2__ */
+/**
+ * csum_unfolded - Calculate the unfolded checksum of a data buffer.
+ *
+ * @buf:   Input buffer
+ * @len:   Input length
+ * @init:  Initial 32-bit checksum, 0 for no pre-computed checksum
+ *
+ * Return: 32-bit unfolded checksum
+ */
+/* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
+__attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
+uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init)
+{
+	return sum_16b(buf, len) + init;
+}
+#endif /* !__AVX2__ */
 
 /**
  * csum() - Compute TCP/IP-style checksum
  * @buf:	Input buffer
  * @len:	Input length
- * @sum:	Initial 32-bit checksum, 0 for no pre-computed checksum
+ * @init:	Initial 32-bit checksum, 0 for no pre-computed checksum
  *
  * Return: 16-bit folded, complemented checksum
  */
@@ -425,7 +440,25 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
 __attribute__((optimize("-fno-strict-aliasing")))	/* See csum_16b() */
 uint16_t csum(const void *buf, size_t len, uint32_t init)
 {
-	return (uint16_t)~csum_fold(sum_16b(buf, len) + init);
+	return (uint16_t)~csum_fold(csum_unfolded(buf, len, init));
 }
 
-#endif /* !__AVX2__ */
+/**
+ * csum_iov() - Calculates the unfolded checksum over an array of IO vectors
+ *
+ * @iov		Pointer to the array of IO vectors
+ * @n		Length of the array
+ * @init	Initial 32-bit checksum, 0 for no pre-computed checksum
+ *
+ * Return: 16-bit folded, complemented checksum
+ */
+/* cppcheck-suppress unusedFunction */
+uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init)
+{
+	unsigned int i;
+
+	for (i = 0; i < n; i++)
+		init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
+
+	return (uint16_t)~csum_fold(init);
+}
diff --git a/checksum.h b/checksum.h
index 21c0310d..cb80ab38 100644
--- a/checksum.h
+++ b/checksum.h
@@ -17,13 +17,15 @@ void csum_ip4_header(struct iphdr *ip4h);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len);
-void csum_icmp4(struct icmphdr *ih, const void *payload, size_t len);
+void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len);
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
 	       const void *payload, size_t len);
 void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t len);
+uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init);
 uint16_t csum(const void *buf, size_t len, uint32_t init);
+uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init);
 
 #endif /* CHECKSUM_H */
-- 
@@ -17,13 +17,15 @@ void csum_ip4_header(struct iphdr *ip4h);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len);
-void csum_icmp4(struct icmphdr *ih, const void *payload, size_t len);
+void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len);
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
 	       const void *payload, size_t len);
 void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t len);
+uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init);
 uint16_t csum(const void *buf, size_t len, uint32_t init);
+uint16_t csum_iov(const struct iovec *iov, size_t n, uint32_t init);
 
 #endif /* CHECKSUM_H */
-- 
2.44.0

[PATCH v2 4/9] util: move IP stuff from util.[ch] to ip.[ch]

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

Introduce ip.[ch] file to encapsulate IP protocol handling functions and
structures.  Modify various files to include the new header ip.h when
it's needed.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-5-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 Makefile     | 10 +++---
 conf.c       |  1 +
 dhcp.c       |  1 +
 flow.c       |  1 +
 fwd.c        |  1 +
 icmp.c       |  1 +
 inany.c      |  1 +
 ip.c         | 72 +++++++++++++++++++++++++++++++++++++++++++
 ip.h         | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 ndp.c        |  1 +
 qrap.c       |  1 +
 tap.c        |  1 +
 tcp.c        |  1 +
 tcp_splice.c |  1 +
 udp.c        |  1 +
 util.c       | 55 ---------------------------------
 util.h       | 76 ----------------------------------------------
 17 files changed, 175 insertions(+), 136 deletions(-)
 create mode 100644 ip.c
 create mode 100644 ip.h

diff --git a/Makefile b/Makefile
index 8f966941..2735797a 100644
--- a/Makefile
+++ b/Makefile
@@ -45,8 +45,8 @@ FLAGS += -DVERSION=\"$(VERSION)\"
 FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS)
 
 PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c flow.c fwd.c \
-	icmp.c igmp.c inany.c iov.c isolation.c lineread.c log.c mld.c ndp.c \
-	netlink.c packet.c passt.c pasta.c pcap.c pif.c tap.c tcp.c \
+	icmp.c igmp.c inany.c iov.c ip.c isolation.c lineread.c log.c mld.c \
+	ndp.c netlink.c packet.c passt.c pasta.c pcap.c pif.c tap.c tcp.c \
 	tcp_splice.c udp.c util.c
 QRAP_SRCS = qrap.c
 SRCS = $(PASST_SRCS) $(QRAP_SRCS)
@@ -54,9 +54,9 @@ SRCS = $(PASST_SRCS) $(QRAP_SRCS)
 MANPAGES = passt.1 pasta.1 qrap.1
 
 PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h fwd.h \
-	flow_table.h icmp.h inany.h iov.h isolation.h lineread.h log.h ndp.h \
-	netlink.h packet.h passt.h pasta.h pcap.h pif.h siphash.h tap.h tcp.h \
-	tcp_conn.h tcp_splice.h udp.h util.h
+	flow_table.h icmp.h inany.h iov.h ip.h isolation.h lineread.h log.h \
+	ndp.h netlink.h packet.h passt.h pasta.h pcap.h pif.h siphash.h tap.h \
+	tcp.h tcp_conn.h tcp_splice.h udp.h util.h
 HEADERS = $(PASST_HEADERS) seccomp.h
 
 C := \#include <linux/tcp.h>\nstruct tcp_info x = { .tcpi_snd_wnd = 0 };
diff --git a/conf.c b/conf.c
index e630140d..4a783b8b 100644
--- a/conf.c
+++ b/conf.c
@@ -35,6 +35,7 @@
 #include <netinet/if_ether.h>
 
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "netlink.h"
 #include "udp.h"
diff --git a/dhcp.c b/dhcp.c
index 11077286..ff4834a3 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -25,6 +25,7 @@
 #include <limits.h>
 
 #include "util.h"
+#include "ip.h"
 #include "checksum.h"
 #include "packet.h"
 #include "passt.h"
diff --git a/flow.c b/flow.c
index d7974d59..5bb24ccf 100644
--- a/flow.c
+++ b/flow.c
@@ -11,6 +11,7 @@
 #include <string.h>
 
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "siphash.h"
 #include "inany.h"
diff --git a/fwd.c b/fwd.c
index 09650b26..a235d131 100644
--- a/fwd.c
+++ b/fwd.c
@@ -21,6 +21,7 @@
 #include <stdio.h>
 
 #include "util.h"
+#include "ip.h"
 #include "fwd.h"
 #include "passt.h"
 #include "lineread.h"
diff --git a/icmp.c b/icmp.c
index fb2fcafc..49d6dd92 100644
--- a/icmp.c
+++ b/icmp.c
@@ -33,6 +33,7 @@
 
 #include "packet.h"
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "tap.h"
 #include "log.h"
diff --git a/inany.c b/inany.c
index 1c165b14..c8479a75 100644
--- a/inany.c
+++ b/inany.c
@@ -13,6 +13,7 @@
 #include <arpa/inet.h>
 
 #include "util.h"
+#include "ip.h"
 #include "siphash.h"
 #include "inany.h"
 
diff --git a/ip.c b/ip.c
new file mode 100644
index 00000000..2cc7f654
--- /dev/null
+++ b/ip.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* PASST - Plug A Simple Socket Transport
+ *  for qemu/UNIX domain socket mode
+ *
+ * PASTA - Pack A Subtle Tap Abstraction
+ *  for network namespace/tap device mode
+ *
+ * ip.c - IP related functions
+ *
+ * Copyright (c) 2020-2021 Red Hat GmbH
+ * Author: Stefano Brivio <sbrivio@redhat.com>
+ */
+
+#include <stddef.h>
+#include "util.h"
+#include "ip.h"
+
+#define IPV6_NH_OPT(nh)							\
+	((nh) == 0   || (nh) == 43  || (nh) == 44  || (nh) == 50  ||	\
+	 (nh) == 51  || (nh) == 60  || (nh) == 135 || (nh) == 139 ||	\
+	 (nh) == 140 || (nh) == 253 || (nh) == 254)
+
+/**
+ * ipv6_l4hdr() - Find pointer to L4 header in IPv6 packet and extract protocol
+ * @p:		Packet pool, packet number @idx has IPv6 header at @offset
+ * @idx:	Index of packet in pool
+ * @offset:	Pre-calculated IPv6 header offset
+ * @proto:	Filled with L4 protocol number
+ * @dlen:	Data length (payload excluding header extensions), set on return
+ *
+ * Return: pointer to L4 header, NULL if not found
+ */
+char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
+		 size_t *dlen)
+{
+	const struct ipv6_opt_hdr *o;
+	const struct ipv6hdr *ip6h;
+	char *base;
+	int hdrlen;
+	uint8_t nh;
+
+	base = packet_get(p, idx, 0, 0, NULL);
+	ip6h = packet_get(p, idx, offset, sizeof(*ip6h), dlen);
+	if (!ip6h)
+		return NULL;
+
+	offset += sizeof(*ip6h);
+
+	nh = ip6h->nexthdr;
+	if (!IPV6_NH_OPT(nh))
+		goto found;
+
+	while ((o = packet_get_try(p, idx, offset, sizeof(*o), dlen))) {
+		nh = o->nexthdr;
+		hdrlen = (o->hdrlen + 1) * 8;
+
+		if (IPV6_NH_OPT(nh))
+			offset += hdrlen;
+		else
+			goto found;
+	}
+
+	return NULL;
+
+found:
+	if (nh == 59)
+		return NULL;
+
+	*proto = nh;
+	return base + offset;
+}
diff --git a/ip.h b/ip.h
new file mode 100644
index 00000000..9be47783
--- /dev/null
+++ b/ip.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright (c) 2021 Red Hat GmbH
+ * Author: Stefano Brivio <sbrivio@redhat.com>
+ */
+
+#ifndef IP_H
+#define IP_H
+
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+
+#define IN4_IS_ADDR_UNSPECIFIED(a) \
+	(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_ANY))
+#define IN4_IS_ADDR_BROADCAST(a) \
+	(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_BROADCAST))
+#define IN4_IS_ADDR_LOOPBACK(a) \
+	(ntohl(((struct in_addr *)(a))->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
+#define IN4_IS_ADDR_MULTICAST(a) \
+	(IN_MULTICAST(ntohl(((struct in_addr *)(a))->s_addr)))
+#define IN4_ARE_ADDR_EQUAL(a, b) \
+	(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
+#define IN4ADDR_LOOPBACK_INIT \
+	{ .s_addr	= htonl_constant(INADDR_LOOPBACK) }
+#define IN4ADDR_ANY_INIT \
+	{ .s_addr	= htonl_constant(INADDR_ANY) }
+
+#define L2_BUF_IP4_INIT(proto)						\
+	{								\
+		.version	= 4,					\
+		.ihl		= 5,					\
+		.tos		= 0,					\
+		.tot_len	= 0,					\
+		.id		= 0,					\
+		.frag_off	= 0,					\
+		.ttl		= 0xff,					\
+		.protocol	= (proto),				\
+		.saddr		= 0,					\
+		.daddr		= 0,					\
+	}
+#define L2_BUF_IP4_PSUM(proto)	((uint32_t)htons_constant(0x4500) +	\
+				 (uint32_t)htons_constant(0xff00 | (proto)))
+
+#define L2_BUF_IP6_INIT(proto)						\
+	{								\
+		.priority	= 0,					\
+		.version	= 6,					\
+		.flow_lbl	= { 0 },				\
+		.payload_len	= 0,					\
+		.nexthdr	= (proto),				\
+		.hop_limit	= 255,					\
+		.saddr		= IN6ADDR_ANY_INIT,			\
+		.daddr		= IN6ADDR_ANY_INIT,			\
+	}
+
+struct ipv6hdr {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+#if __BYTE_ORDER == __BIG_ENDIAN
+	uint8_t			version:4,
+				priority:4;
+#else
+	uint8_t			priority:4,
+				version:4;
+#endif
+#pragma GCC diagnostic pop
+	uint8_t			flow_lbl[3];
+
+	uint16_t		payload_len;
+	uint8_t			nexthdr;
+	uint8_t			hop_limit;
+
+	struct in6_addr		saddr;
+	struct in6_addr		daddr;
+};
+
+struct ipv6_opt_hdr {
+	uint8_t			nexthdr;
+	uint8_t			hdrlen;
+	/*
+	 * TLV encoded option data follows.
+	 */
+} __attribute__((packed));	/* required for some archs */
+
+char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
+		 size_t *dlen);
+#endif /* IP_H */
diff --git a/ndp.c b/ndp.c
index 4c85ab8b..c58f4b22 100644
--- a/ndp.c
+++ b/ndp.c
@@ -28,6 +28,7 @@
 
 #include "checksum.h"
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "tap.h"
 #include "log.h"
diff --git a/qrap.c b/qrap.c
index 97f350a4..d5967062 100644
--- a/qrap.c
+++ b/qrap.c
@@ -32,6 +32,7 @@
 #include <linux/icmpv6.h>
 
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "arp.h"
 
diff --git a/tap.c b/tap.c
index 3a666212..d35d8944 100644
--- a/tap.c
+++ b/tap.c
@@ -45,6 +45,7 @@
 
 #include "checksum.h"
 #include "util.h"
+#include "ip.h"
 #include "iov.h"
 #include "passt.h"
 #include "arp.h"
diff --git a/tcp.c b/tcp.c
index 560d1d49..e0588f92 100644
--- a/tcp.c
+++ b/tcp.c
@@ -290,6 +290,7 @@
 
 #include "checksum.h"
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "tap.h"
 #include "siphash.h"
diff --git a/tcp_splice.c b/tcp_splice.c
index 4957abb8..d066112c 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -49,6 +49,7 @@
 #include <sys/socket.h>
 
 #include "util.h"
+#include "ip.h"
 #include "passt.h"
 #include "log.h"
 #include "tcp_splice.h"
diff --git a/udp.c b/udp.c
index cb7c31f7..26774df7 100644
--- a/udp.c
+++ b/udp.c
@@ -113,6 +113,7 @@
 
 #include "checksum.h"
 #include "util.h"
+#include "ip.h"
 #include "siphash.h"
 #include "inany.h"
 #include "passt.h"
diff --git a/util.c b/util.c
index 81449b78..bac5a534 100644
--- a/util.c
+++ b/util.c
@@ -32,61 +32,6 @@
 #include "packet.h"
 #include "log.h"
 
-#define IPV6_NH_OPT(nh)							\
-	((nh) == 0   || (nh) == 43  || (nh) == 44  || (nh) == 50  ||	\
-	 (nh) == 51  || (nh) == 60  || (nh) == 135 || (nh) == 139 ||	\
-	 (nh) == 140 || (nh) == 253 || (nh) == 254)
-
-/**
- * ipv6_l4hdr() - Find pointer to L4 header in IPv6 packet and extract protocol
- * @p:		Packet pool, packet number @idx has IPv6 header at @offset
- * @idx:	Index of packet in pool
- * @offset:	Pre-calculated IPv6 header offset
- * @proto:	Filled with L4 protocol number
- * @dlen:	Data length (payload excluding header extensions), set on return
- *
- * Return: pointer to L4 header, NULL if not found
- */
-char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
-		 size_t *dlen)
-{
-	const struct ipv6_opt_hdr *o;
-	const struct ipv6hdr *ip6h;
-	char *base;
-	int hdrlen;
-	uint8_t nh;
-
-	base = packet_get(p, idx, 0, 0, NULL);
-	ip6h = packet_get(p, idx, offset, sizeof(*ip6h), dlen);
-	if (!ip6h)
-		return NULL;
-
-	offset += sizeof(*ip6h);
-
-	nh = ip6h->nexthdr;
-	if (!IPV6_NH_OPT(nh))
-		goto found;
-
-	while ((o = packet_get_try(p, idx, offset, sizeof(*o), dlen))) {
-		nh = o->nexthdr;
-		hdrlen = (o->hdrlen + 1) * 8;
-
-		if (IPV6_NH_OPT(nh))
-			offset += hdrlen;
-		else
-			goto found;
-	}
-
-	return NULL;
-
-found:
-	if (nh == 59)
-		return NULL;
-
-	*proto = nh;
-	return base + offset;
-}
-
 /**
  * sock_l4() - Create and bind socket for given L4, add to epoll list
  * @c:		Execution context
diff --git a/util.h b/util.h
index 55513490..25e54a77 100644
--- a/util.h
+++ b/util.h
@@ -110,22 +110,6 @@
 #define	htonl_constant(x)	(__bswap_constant_32(x))
 #endif
 
-#define IN4_IS_ADDR_UNSPECIFIED(a) \
-	(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_ANY))
-#define IN4_IS_ADDR_BROADCAST(a) \
-	(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_BROADCAST))
-#define IN4_IS_ADDR_LOOPBACK(a) \
-	(ntohl(((struct in_addr *)(a))->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
-#define IN4_IS_ADDR_MULTICAST(a) \
-	(IN_MULTICAST(ntohl(((struct in_addr *)(a))->s_addr)))
-#define IN4_ARE_ADDR_EQUAL(a, b) \
-	(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
-#define IN4ADDR_LOOPBACK_INIT \
-	{ .s_addr	= htonl_constant(INADDR_LOOPBACK) }
-#define IN4ADDR_ANY_INIT \
-	{ .s_addr	= htonl_constant(INADDR_ANY) }
-
-
 #define NS_FN_STACK_SIZE	(RLIMIT_STACK_VAL * 1024 / 8)
 int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 	     void *arg);
@@ -138,34 +122,6 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 			 (void *)(arg));				\
 	} while (0)
 
-#define L2_BUF_IP4_INIT(proto)						\
-	{								\
-		.version	= 4,					\
-		.ihl		= 5,					\
-		.tos		= 0,					\
-		.tot_len	= 0,					\
-		.id		= 0,					\
-		.frag_off	= 0,					\
-		.ttl		= 0xff,					\
-		.protocol	= (proto),				\
-		.saddr		= 0,					\
-		.daddr		= 0,					\
-	}
-#define L2_BUF_IP4_PSUM(proto)	((uint32_t)htons_constant(0x4500) +	\
-				 (uint32_t)htons_constant(0xff00 | (proto)))
-
-#define L2_BUF_IP6_INIT(proto)						\
-	{								\
-		.priority	= 0,					\
-		.version	= 6,					\
-		.flow_lbl	= { 0 },				\
-		.payload_len	= 0,					\
-		.nexthdr	= (proto),				\
-		.hop_limit	= 255,					\
-		.saddr		= IN6ADDR_ANY_INIT,			\
-		.daddr		= IN6ADDR_ANY_INIT,			\
-	}
-
 #define RCVBUF_BIG		(2UL * 1024 * 1024)
 #define SNDBUF_BIG		(4UL * 1024 * 1024)
 #define SNDBUF_SMALL		(128UL * 1024)
@@ -173,45 +129,13 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 #include <net/if.h>
 #include <limits.h>
 #include <stdint.h>
-#include <netinet/ip6.h>
 
 #include "packet.h"
 
 struct ctx;
 
-struct ipv6hdr {
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wpedantic"
-#if __BYTE_ORDER == __BIG_ENDIAN
-	uint8_t			version:4,
-				priority:4;
-#else
-	uint8_t			priority:4,
-				version:4;
-#endif
-#pragma GCC diagnostic pop
-	uint8_t			flow_lbl[3];
-
-	uint16_t		payload_len;
-	uint8_t			nexthdr;
-	uint8_t			hop_limit;
-
-	struct in6_addr		saddr;
-	struct in6_addr		daddr;
-};
-
-struct ipv6_opt_hdr {
-	uint8_t			nexthdr;
-	uint8_t			hdrlen;
-	/*
-	 * TLV encoded option data follows.
-	 */
-} __attribute__((packed));	/* required for some archs */
-
 /* cppcheck-suppress funcArgNamesDifferent */
 __attribute__ ((weak)) int ffsl(long int i) { return __builtin_ffsl(i); }
-char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
-		 size_t *dlen);
 int sock_l4(const struct ctx *c, sa_family_t af, uint8_t proto,
 	    const void *bind_addr, const char *ifname, uint16_t port,
 	    uint32_t data);
-- 
@@ -110,22 +110,6 @@
 #define	htonl_constant(x)	(__bswap_constant_32(x))
 #endif
 
-#define IN4_IS_ADDR_UNSPECIFIED(a) \
-	(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_ANY))
-#define IN4_IS_ADDR_BROADCAST(a) \
-	(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_BROADCAST))
-#define IN4_IS_ADDR_LOOPBACK(a) \
-	(ntohl(((struct in_addr *)(a))->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
-#define IN4_IS_ADDR_MULTICAST(a) \
-	(IN_MULTICAST(ntohl(((struct in_addr *)(a))->s_addr)))
-#define IN4_ARE_ADDR_EQUAL(a, b) \
-	(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
-#define IN4ADDR_LOOPBACK_INIT \
-	{ .s_addr	= htonl_constant(INADDR_LOOPBACK) }
-#define IN4ADDR_ANY_INIT \
-	{ .s_addr	= htonl_constant(INADDR_ANY) }
-
-
 #define NS_FN_STACK_SIZE	(RLIMIT_STACK_VAL * 1024 / 8)
 int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 	     void *arg);
@@ -138,34 +122,6 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 			 (void *)(arg));				\
 	} while (0)
 
-#define L2_BUF_IP4_INIT(proto)						\
-	{								\
-		.version	= 4,					\
-		.ihl		= 5,					\
-		.tos		= 0,					\
-		.tot_len	= 0,					\
-		.id		= 0,					\
-		.frag_off	= 0,					\
-		.ttl		= 0xff,					\
-		.protocol	= (proto),				\
-		.saddr		= 0,					\
-		.daddr		= 0,					\
-	}
-#define L2_BUF_IP4_PSUM(proto)	((uint32_t)htons_constant(0x4500) +	\
-				 (uint32_t)htons_constant(0xff00 | (proto)))
-
-#define L2_BUF_IP6_INIT(proto)						\
-	{								\
-		.priority	= 0,					\
-		.version	= 6,					\
-		.flow_lbl	= { 0 },				\
-		.payload_len	= 0,					\
-		.nexthdr	= (proto),				\
-		.hop_limit	= 255,					\
-		.saddr		= IN6ADDR_ANY_INIT,			\
-		.daddr		= IN6ADDR_ANY_INIT,			\
-	}
-
 #define RCVBUF_BIG		(2UL * 1024 * 1024)
 #define SNDBUF_BIG		(4UL * 1024 * 1024)
 #define SNDBUF_SMALL		(128UL * 1024)
@@ -173,45 +129,13 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 #include <net/if.h>
 #include <limits.h>
 #include <stdint.h>
-#include <netinet/ip6.h>
 
 #include "packet.h"
 
 struct ctx;
 
-struct ipv6hdr {
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wpedantic"
-#if __BYTE_ORDER == __BIG_ENDIAN
-	uint8_t			version:4,
-				priority:4;
-#else
-	uint8_t			priority:4,
-				version:4;
-#endif
-#pragma GCC diagnostic pop
-	uint8_t			flow_lbl[3];
-
-	uint16_t		payload_len;
-	uint8_t			nexthdr;
-	uint8_t			hop_limit;
-
-	struct in6_addr		saddr;
-	struct in6_addr		daddr;
-};
-
-struct ipv6_opt_hdr {
-	uint8_t			nexthdr;
-	uint8_t			hdrlen;
-	/*
-	 * TLV encoded option data follows.
-	 */
-} __attribute__((packed));	/* required for some archs */
-
 /* cppcheck-suppress funcArgNamesDifferent */
 __attribute__ ((weak)) int ffsl(long int i) { return __builtin_ffsl(i); }
-char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
-		 size_t *dlen);
 int sock_l4(const struct ctx *c, sa_family_t af, uint8_t proto,
 	    const void *bind_addr, const char *ifname, uint16_t port,
 	    uint32_t data);
-- 
2.44.0

[PATCH v2 5/9] udp: little cleanup in udp_update_hdrX() to prepare future changes

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

in udp_update_hdr4():

    Assign the source address to src, either b->s_in.sin_addr,
    c->ip4.dns_match or c->ip4.gw and then set b->iph.saddr to src->s_addr.

in udp_update_hdr6():

   Assign the source address to src, either b->s_in6.sin6_addr,
   c->ip6.dns_match, c->ip6.gw or c->ip6.addr_ll.
   Assign the destination to dst, either c->ip6.addr_seen or
   &c->ip6.addr_ll_seen.
   Then set dst to b->ip6h.daddr and src to b->ip6h.saddr.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-ID: <20240303135114.1023026-6-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 udp.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/udp.c b/udp.c
index 26774df7..2b41a1bd 100644
--- a/udp.c
+++ b/udp.c
@@ -588,7 +588,7 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 			      const struct timespec *now)
 {
 	struct udp4_l2_buf_t *b = &udp4_l2_buf[n];
-	struct in_addr *src;
+	const struct in_addr *src;
 	in_port_t src_port;
 	size_t ip_len;
 
@@ -602,10 +602,9 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 
 	if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_match) &&
 	    IN4_ARE_ADDR_EQUAL(src, &c->ip4.dns_host) && src_port == 53) {
-		b->iph.saddr = c->ip4.dns_match.s_addr;
+		src = &c->ip4.dns_match;
 	} else if (IN4_IS_ADDR_LOOPBACK(src) ||
 		   IN4_ARE_ADDR_EQUAL(src, &c->ip4.addr_seen)) {
-		b->iph.saddr = c->ip4.gw.s_addr;
 		udp_tap_map[V4][src_port].ts = now->tv_sec;
 		udp_tap_map[V4][src_port].flags |= PORT_LOCAL;
 
@@ -615,9 +614,10 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 			udp_tap_map[V4][src_port].flags &= ~PORT_LOOPBACK;
 
 		bitmap_set(udp_act[V4][UDP_ACT_TAP], src_port);
-	} else {
-		b->iph.saddr = src->s_addr;
+
+		src = &c->ip4.gw;
 	}
+	b->iph.saddr = src->s_addr;
 
 	udp_update_check4(b);
 	b->uh.source = b->s_in.sin_port;
@@ -640,10 +640,11 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 			      const struct timespec *now)
 {
 	struct udp6_l2_buf_t *b = &udp6_l2_buf[n];
-	struct in6_addr *src;
+	const struct in6_addr *src, *dst;
 	in_port_t src_port;
 	size_t ip_len;
 
+	dst = &c->ip6.addr_seen;
 	src = &b->s_in6.sin6_addr;
 	src_port = ntohs(b->s_in6.sin6_port);
 
@@ -652,23 +653,14 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 	b->ip6h.payload_len = htons(udp6_l2_mh_sock[n].msg_len + sizeof(b->uh));
 
 	if (IN6_IS_ADDR_LINKLOCAL(src)) {
-		b->ip6h.daddr = c->ip6.addr_ll_seen;
-		b->ip6h.saddr = b->s_in6.sin6_addr;
+		dst = &c->ip6.addr_ll_seen;
 	} else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_match) &&
 		   IN6_ARE_ADDR_EQUAL(src, &c->ip6.dns_host) &&
 		   src_port == 53) {
-		b->ip6h.daddr = c->ip6.addr_seen;
-		b->ip6h.saddr = c->ip6.dns_match;
+		src = &c->ip6.dns_match;
 	} else if (IN6_IS_ADDR_LOOPBACK(src)			||
 		   IN6_ARE_ADDR_EQUAL(src, &c->ip6.addr_seen)	||
 		   IN6_ARE_ADDR_EQUAL(src, &c->ip6.addr)) {
-		b->ip6h.daddr = c->ip6.addr_ll_seen;
-
-		if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
-			b->ip6h.saddr = c->ip6.gw;
-		else
-			b->ip6h.saddr = c->ip6.addr_ll;
-
 		udp_tap_map[V6][src_port].ts = now->tv_sec;
 		udp_tap_map[V6][src_port].flags |= PORT_LOCAL;
 
@@ -683,10 +675,17 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 			udp_tap_map[V6][src_port].flags &= ~PORT_GUA;
 
 		bitmap_set(udp_act[V6][UDP_ACT_TAP], src_port);
-	} else {
-		b->ip6h.daddr = c->ip6.addr_seen;
-		b->ip6h.saddr = b->s_in6.sin6_addr;
+
+		dst = &c->ip6.addr_ll_seen;
+
+		if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
+			src = &c->ip6.gw;
+		else
+			src = &c->ip6.addr_ll;
+
 	}
+	b->ip6h.daddr = *dst;
+	b->ip6h.saddr = *src;
 
 	b->uh.source = b->s_in6.sin6_port;
 	b->uh.dest = htons(dstport);
-- 
@@ -588,7 +588,7 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 			      const struct timespec *now)
 {
 	struct udp4_l2_buf_t *b = &udp4_l2_buf[n];
-	struct in_addr *src;
+	const struct in_addr *src;
 	in_port_t src_port;
 	size_t ip_len;
 
@@ -602,10 +602,9 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 
 	if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_match) &&
 	    IN4_ARE_ADDR_EQUAL(src, &c->ip4.dns_host) && src_port == 53) {
-		b->iph.saddr = c->ip4.dns_match.s_addr;
+		src = &c->ip4.dns_match;
 	} else if (IN4_IS_ADDR_LOOPBACK(src) ||
 		   IN4_ARE_ADDR_EQUAL(src, &c->ip4.addr_seen)) {
-		b->iph.saddr = c->ip4.gw.s_addr;
 		udp_tap_map[V4][src_port].ts = now->tv_sec;
 		udp_tap_map[V4][src_port].flags |= PORT_LOCAL;
 
@@ -615,9 +614,10 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 			udp_tap_map[V4][src_port].flags &= ~PORT_LOOPBACK;
 
 		bitmap_set(udp_act[V4][UDP_ACT_TAP], src_port);
-	} else {
-		b->iph.saddr = src->s_addr;
+
+		src = &c->ip4.gw;
 	}
+	b->iph.saddr = src->s_addr;
 
 	udp_update_check4(b);
 	b->uh.source = b->s_in.sin_port;
@@ -640,10 +640,11 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 			      const struct timespec *now)
 {
 	struct udp6_l2_buf_t *b = &udp6_l2_buf[n];
-	struct in6_addr *src;
+	const struct in6_addr *src, *dst;
 	in_port_t src_port;
 	size_t ip_len;
 
+	dst = &c->ip6.addr_seen;
 	src = &b->s_in6.sin6_addr;
 	src_port = ntohs(b->s_in6.sin6_port);
 
@@ -652,23 +653,14 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 	b->ip6h.payload_len = htons(udp6_l2_mh_sock[n].msg_len + sizeof(b->uh));
 
 	if (IN6_IS_ADDR_LINKLOCAL(src)) {
-		b->ip6h.daddr = c->ip6.addr_ll_seen;
-		b->ip6h.saddr = b->s_in6.sin6_addr;
+		dst = &c->ip6.addr_ll_seen;
 	} else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_match) &&
 		   IN6_ARE_ADDR_EQUAL(src, &c->ip6.dns_host) &&
 		   src_port == 53) {
-		b->ip6h.daddr = c->ip6.addr_seen;
-		b->ip6h.saddr = c->ip6.dns_match;
+		src = &c->ip6.dns_match;
 	} else if (IN6_IS_ADDR_LOOPBACK(src)			||
 		   IN6_ARE_ADDR_EQUAL(src, &c->ip6.addr_seen)	||
 		   IN6_ARE_ADDR_EQUAL(src, &c->ip6.addr)) {
-		b->ip6h.daddr = c->ip6.addr_ll_seen;
-
-		if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
-			b->ip6h.saddr = c->ip6.gw;
-		else
-			b->ip6h.saddr = c->ip6.addr_ll;
-
 		udp_tap_map[V6][src_port].ts = now->tv_sec;
 		udp_tap_map[V6][src_port].flags |= PORT_LOCAL;
 
@@ -683,10 +675,17 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 			udp_tap_map[V6][src_port].flags &= ~PORT_GUA;
 
 		bitmap_set(udp_act[V6][UDP_ACT_TAP], src_port);
-	} else {
-		b->ip6h.daddr = c->ip6.addr_seen;
-		b->ip6h.saddr = b->s_in6.sin6_addr;
+
+		dst = &c->ip6.addr_ll_seen;
+
+		if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
+			src = &c->ip6.gw;
+		else
+			src = &c->ip6.addr_ll;
+
 	}
+	b->ip6h.daddr = *dst;
+	b->ip6h.saddr = *src;
 
 	b->uh.source = b->s_in6.sin6_port;
 	b->uh.dest = htons(dstport);
-- 
2.44.0

[PATCH v2 6/9] checksum: use csum_ip4_header() in udp.c and tcp.c

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

We can find the same function to compute the IPv4 header
checksum in tcp.c, udp.c and tap.c

Use the function defined for tap.c, csum_ip4_header(), but
with the code used in tcp.c and udp.c as it doesn't need a fully
initialiazed IPv4 header, only protocol, tot_len, saddr and daddr.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-7-lvivier@redhat.com>
[dwg: Fix weird cppcheck regression; it appears to be a problem
 in pre-existing code, but somehow this patch is exposing it]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 checksum.c | 24 +++++++++++++++++++-----
 checksum.h |  3 ++-
 tap.c      |  2 +-
 tcp.c      | 24 +++---------------------
 udp.c      | 20 ++------------------
 5 files changed, 27 insertions(+), 46 deletions(-)

diff --git a/checksum.c b/checksum.c
index 643957b5..1ac79758 100644
--- a/checksum.c
+++ b/checksum.c
@@ -57,6 +57,7 @@
 #include <linux/icmpv6.h>
 
 #include "util.h"
+#include "ip.h"
 #include "checksum.h"
 
 /* Checksums are optional for UDP over IPv4, so we usually just set
@@ -114,13 +115,26 @@ uint16_t csum_fold(uint32_t sum)
 }
 
 /**
- * csum_ip4_header() - Calculate and set IPv4 header checksum
- * @ip4h:	IPv4 header
+ * csum_ip4_header() - Calculate IPv4 header checksum
+ * @tot_len:	IPv4 payload length (data + IP header, network order)
+ * @protocol:	Protocol number (network order)
+ * @saddr:	IPv4 source address (network order)
+ * @daddr:	IPv4 destination address (network order)
+ *
+ * Return: 16-bit folded sum of the IPv4 header
  */
-void csum_ip4_header(struct iphdr *ip4h)
+uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
+			 struct in_addr saddr, struct in_addr daddr)
 {
-	ip4h->check = 0;
-	ip4h->check = csum(ip4h, (size_t)ip4h->ihl * 4, 0);
+	uint32_t sum = L2_BUF_IP4_PSUM(protocol);
+
+	sum += tot_len;
+	sum += (saddr.s_addr >> 16) & 0xffff;
+	sum += saddr.s_addr & 0xffff;
+	sum += (daddr.s_addr >> 16) & 0xffff;
+	sum += daddr.s_addr & 0xffff;
+
+	return ~csum_fold(sum);
 }
 
 /**
diff --git a/checksum.h b/checksum.h
index cb80ab38..996f456b 100644
--- a/checksum.h
+++ b/checksum.h
@@ -13,7 +13,8 @@ struct icmp6hdr;
 uint32_t sum_16b(const void *buf, size_t len);
 uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
-void csum_ip4_header(struct iphdr *ip4h);
+uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
+			 struct in_addr saddr, struct in_addr daddr);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len);
diff --git a/tap.c b/tap.c
index d35d8944..f971461c 100644
--- a/tap.c
+++ b/tap.c
@@ -161,7 +161,7 @@ static void *tap_push_ip4h(char *buf, struct in_addr src, struct in_addr dst,
 	ip4h->protocol = proto;
 	ip4h->saddr = src.s_addr;
 	ip4h->daddr = dst.s_addr;
-	csum_ip4_header(ip4h);
+	ip4h->check = csum_ip4_header(ip4h->tot_len, proto, src, dst);
 	return ip4h + 1;
 }
 
diff --git a/tcp.c b/tcp.c
index e0588f92..7fb9dba9 100644
--- a/tcp.c
+++ b/tcp.c
@@ -935,23 +935,6 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
 		trace("TCP: failed to set SO_SNDBUF to %i", v);
 }
 
-/**
- * tcp_update_check_ip4() - Update IPv4 with variable parts from stored one
- * @buf:	L2 packet buffer with final IPv4 header
- */
-static void tcp_update_check_ip4(struct tcp4_l2_buf_t *buf)
-{
-	uint32_t sum = L2_BUF_IP4_PSUM(IPPROTO_TCP);
-
-	sum += buf->iph.tot_len;
-	sum += (buf->iph.saddr >> 16) & 0xffff;
-	sum += buf->iph.saddr & 0xffff;
-	sum += (buf->iph.daddr >> 16) & 0xffff;
-	sum += buf->iph.daddr & 0xffff;
-
-	buf->iph.check = (uint16_t)~csum_fold(sum);
-}
-
 /**
  * tcp_update_check_tcp4() - Update TCP checksum from stored one
  * @buf:	L2 packet buffer with final IPv4 header
@@ -1394,10 +1377,9 @@ do {									\
 		b->iph.saddr = a4->s_addr;
 		b->iph.daddr = c->ip4.addr_seen.s_addr;
 
-		if (check)
-			b->iph.check = *check;
-		else
-			tcp_update_check_ip4(b);
+		b->iph.check = check ? *check :
+			       csum_ip4_header(b->iph.tot_len, IPPROTO_TCP,
+					       *a4, c->ip4.addr_seen);
 
 		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
 
diff --git a/udp.c b/udp.c
index 2b41a1bd..fb8373be 100644
--- a/udp.c
+++ b/udp.c
@@ -275,23 +275,6 @@ static void udp_invert_portmap(struct udp_fwd_ports *fwd)
 	}
 }
 
-/**
- * udp_update_check4() - Update checksum with variable parts from stored one
- * @buf:	L2 packet buffer with final IPv4 header
- */
-static void udp_update_check4(struct udp4_l2_buf_t *buf)
-{
-	uint32_t sum = L2_BUF_IP4_PSUM(IPPROTO_UDP);
-
-	sum += buf->iph.tot_len;
-	sum += (buf->iph.saddr >> 16) & 0xffff;
-	sum += buf->iph.saddr & 0xffff;
-	sum += (buf->iph.daddr >> 16) & 0xffff;
-	sum += buf->iph.daddr & 0xffff;
-
-	buf->iph.check = (uint16_t)~csum_fold(sum);
-}
-
 /**
  * udp_update_l2_buf() - Update L2 buffers with Ethernet and IPv4 addresses
  * @eth_d:	Ethernet destination address, NULL if unchanged
@@ -619,7 +602,8 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 	}
 	b->iph.saddr = src->s_addr;
 
-	udp_update_check4(b);
+	b->iph.check = csum_ip4_header(b->iph.tot_len, IPPROTO_UDP,
+				       *src, c->ip4.addr_seen);
 	b->uh.source = b->s_in.sin_port;
 	b->uh.dest = htons(dstport);
 	b->uh.len = htons(udp4_l2_mh_sock[n].msg_len + sizeof(b->uh));
-- 
@@ -275,23 +275,6 @@ static void udp_invert_portmap(struct udp_fwd_ports *fwd)
 	}
 }
 
-/**
- * udp_update_check4() - Update checksum with variable parts from stored one
- * @buf:	L2 packet buffer with final IPv4 header
- */
-static void udp_update_check4(struct udp4_l2_buf_t *buf)
-{
-	uint32_t sum = L2_BUF_IP4_PSUM(IPPROTO_UDP);
-
-	sum += buf->iph.tot_len;
-	sum += (buf->iph.saddr >> 16) & 0xffff;
-	sum += buf->iph.saddr & 0xffff;
-	sum += (buf->iph.daddr >> 16) & 0xffff;
-	sum += buf->iph.daddr & 0xffff;
-
-	buf->iph.check = (uint16_t)~csum_fold(sum);
-}
-
 /**
  * udp_update_l2_buf() - Update L2 buffers with Ethernet and IPv4 addresses
  * @eth_d:	Ethernet destination address, NULL if unchanged
@@ -619,7 +602,8 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 	}
 	b->iph.saddr = src->s_addr;
 
-	udp_update_check4(b);
+	b->iph.check = csum_ip4_header(b->iph.tot_len, IPPROTO_UDP,
+				       *src, c->ip4.addr_seen);
 	b->uh.source = b->s_in.sin_port;
 	b->uh.dest = htons(dstport);
 	b->uh.len = htons(udp4_l2_mh_sock[n].msg_len + sizeof(b->uh));
-- 
2.44.0

[PATCH v2 7/9] checksum: introduce functions to compute the header part checksum for TCP/UDP

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

The TCP and UDP checksums are computed using the data in the TCP/UDP
payload but also some informations in the IP header (protocol,
length, source and destination addresses).

We add two functions, proto_ipv4_header_psum() and
proto_ipv6_header_psum(), to compute the checksum of the IP
header part.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-ID: <20240303135114.1023026-8-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 checksum.c | 67 ++++++++++++++++++++++++++++++++++++++++++------------
 checksum.h |  5 ++++
 tcp.c      | 50 +++++++++++++++++++---------------------
 udp.c      | 18 ++++++++-------
 4 files changed, 90 insertions(+), 50 deletions(-)

diff --git a/checksum.c b/checksum.c
index 1ac79758..f8a7b539 100644
--- a/checksum.c
+++ b/checksum.c
@@ -137,6 +137,29 @@ uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
 	return ~csum_fold(sum);
 }
 
+/**
+ * proto_ipv4_header_psum() - Calculates the partial checksum of an
+ * 			      IPv4 header for UDP or TCP
+ * @tot_len:	IPv4 Payload length (host order)
+ * @proto:	Protocol number (host order)
+ * @saddr:	Source address  (network order)
+ * @daddr:	Destination address (network order)
+ * Returns:	Partial checksum of the IPv4 header
+ */
+uint32_t proto_ipv4_header_psum(uint16_t tot_len, uint8_t protocol,
+				struct in_addr saddr, struct in_addr daddr)
+{
+	uint32_t psum = htons(protocol);
+
+	psum += (saddr.s_addr >> 16) & 0xffff;
+	psum += saddr.s_addr & 0xffff;
+	psum += (daddr.s_addr >> 16) & 0xffff;
+	psum += daddr.s_addr & 0xffff;
+	psum += htons(tot_len);
+
+	return psum;
+}
+
 /**
  * csum_udp4() - Calculate and set checksum for a UDP over IPv4 packet
  * @udp4hr:	UDP header, initialised apart from checksum
@@ -153,14 +176,10 @@ void csum_udp4(struct udphdr *udp4hr,
 	udp4hr->check = 0;
 
 	if (UDP4_REAL_CHECKSUMS) {
-		/* UNTESTED: if we did want real UDPv4 checksums, this
-		 * is roughly what we'd need */
-		uint32_t psum = csum_fold(saddr.s_addr)
-			+ csum_fold(daddr.s_addr)
-			+ htons(len + sizeof(*udp4hr))
-			+ htons(IPPROTO_UDP);
-		/* Add in partial checksum for the UDP header alone */
-		psum += sum_16b(udp4hr, sizeof(*udp4hr));
+		uint16_t tot_len = len + sizeof(struct udphdr);
+		uint32_t psum = proto_ipv4_header_psum(tot_len, IPPROTO_UDP,
+						       saddr, daddr);
+		psum = csum_unfolded(udp4hr, sizeof(struct udphdr), psum);
 		udp4hr->check = csum(payload, len, psum);
 	}
 }
@@ -183,6 +202,27 @@ void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len)
 	icmp4hr->checksum = csum(payload, len, psum);
 }
 
+/**
+ * proto_ipv6_header_psum() - Calculates the partial checksum of an
+ * 			      IPv6 header for UDP or TCP
+ * @payload_len:	IPv6 payload length (host order)
+ * @proto:		Protocol number (host order)
+ * @saddr:		Source address (network order)
+ * @daddr:		Destination address (network order)
+ * Returns:	Partial checksum of the IPv6 header
+ */
+uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
+				const struct in6_addr *saddr,
+				const struct in6_addr *daddr)
+{
+	uint32_t sum = htons(protocol) + htons(payload_len);
+
+	sum += sum_16b(saddr, sizeof(*saddr));
+	sum += sum_16b(daddr, sizeof(*daddr));
+
+	return sum;
+}
+
 /**
  * csum_udp6() - Calculate and set checksum for a UDP over IPv6 packet
  * @udp6hr:	UDP header, initialised apart from checksum
@@ -193,14 +233,11 @@ void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
 	       const void *payload, size_t len)
 {
-	/* Partial checksum for the pseudo-IPv6 header */
-	uint32_t psum = sum_16b(saddr, sizeof(*saddr)) +
-		        sum_16b(daddr, sizeof(*daddr)) +
-		        htons(len + sizeof(*udp6hr)) + htons(IPPROTO_UDP);
-
+	uint32_t psum = proto_ipv6_header_psum(len + sizeof(struct udphdr),
+					       IPPROTO_UDP, saddr, daddr);
 	udp6hr->check = 0;
-	/* Add in partial checksum for the UDP header alone */
-	psum += sum_16b(udp6hr, sizeof(*udp6hr));
+
+	psum = csum_unfolded(udp6hr, sizeof(struct udphdr), psum);
 	udp6hr->check = csum(payload, len, psum);
 }
 
diff --git a/checksum.h b/checksum.h
index 996f456b..0f396767 100644
--- a/checksum.h
+++ b/checksum.h
@@ -15,10 +15,15 @@ uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
 uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
 			 struct in_addr saddr, struct in_addr daddr);
+uint32_t proto_ipv4_header_psum(uint16_t tot_len, uint8_t protocol,
+				struct in_addr saddr, struct in_addr daddr);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
 	       const void *payload, size_t len);
 void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len);
+uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
+				const struct in6_addr *saddr,
+				const struct in6_addr *daddr);
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
 	       const void *payload, size_t len);
diff --git a/tcp.c b/tcp.c
index 7fb9dba9..a7156ee1 100644
--- a/tcp.c
+++ b/tcp.c
@@ -937,41 +937,33 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
 
 /**
  * tcp_update_check_tcp4() - Update TCP checksum from stored one
- * @buf:	L2 packet buffer with final IPv4 header
+ * @iph:	IPv4 header
+ * @th:		TCP header followed by TCP payload
  */
-static void tcp_update_check_tcp4(struct tcp4_l2_buf_t *buf)
+static void tcp_update_check_tcp4(const struct iphdr *iph, struct tcphdr *th)
 {
-	uint16_t tlen = ntohs(buf->iph.tot_len) - 20;
-	uint32_t sum = htons(IPPROTO_TCP);
+	uint16_t tlen = ntohs(iph->tot_len) - sizeof(struct iphdr);
+	struct in_addr saddr = { .s_addr = iph->saddr };
+	struct in_addr daddr = { .s_addr = iph->daddr };
+	uint32_t sum = proto_ipv4_header_psum(tlen, IPPROTO_TCP, saddr, daddr);
 
-	sum += (buf->iph.saddr >> 16) & 0xffff;
-	sum += buf->iph.saddr & 0xffff;
-	sum += (buf->iph.daddr >> 16) & 0xffff;
-	sum += buf->iph.daddr & 0xffff;
-	sum += htons(ntohs(buf->iph.tot_len) - 20);
-
-	buf->th.check = 0;
-	buf->th.check = csum(&buf->th, tlen, sum);
+	th->check = 0;
+	th->check = csum(th, tlen, sum);
 }
 
 /**
  * tcp_update_check_tcp6() - Calculate TCP checksum for IPv6
- * @buf:	L2 packet buffer with final IPv6 header
+ * @ip6h:	IPv6 header
+ * @th:		TCP header followed by TCP payload
  */
-static void tcp_update_check_tcp6(struct tcp6_l2_buf_t *buf)
+static void tcp_update_check_tcp6(struct ipv6hdr *ip6h, struct tcphdr *th)
 {
-	int len = ntohs(buf->ip6h.payload_len) + sizeof(struct ipv6hdr);
-
-	buf->ip6h.hop_limit = IPPROTO_TCP;
-	buf->ip6h.version = 0;
-	buf->ip6h.nexthdr = 0;
+	uint16_t payload_len = ntohs(ip6h->payload_len);
+	uint32_t sum = proto_ipv6_header_psum(payload_len, IPPROTO_TCP,
+					      &ip6h->saddr, &ip6h->daddr);
 
-	buf->th.check = 0;
-	buf->th.check = csum(&buf->ip6h, len, 0);
-
-	buf->ip6h.hop_limit = 255;
-	buf->ip6h.version = 6;
-	buf->ip6h.nexthdr = IPPROTO_TCP;
+	th->check = 0;
+	th->check = csum(th, payload_len, sum);
 }
 
 /**
@@ -1383,7 +1375,7 @@ do {									\
 
 		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
 
-		tcp_update_check_tcp4(b);
+		tcp_update_check_tcp4(&b->iph, &b->th);
 
 		tlen = tap_iov_len(c, &b->taph, ip_len);
 	} else {
@@ -1402,7 +1394,11 @@ do {									\
 
 		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
 
-		tcp_update_check_tcp6(b);
+		tcp_update_check_tcp6(&b->ip6h, &b->th);
+
+		b->ip6h.hop_limit = 255;
+		b->ip6h.version = 6;
+		b->ip6h.nexthdr = IPPROTO_TCP;
 
 		b->ip6h.flow_lbl[0] = (conn->sock >> 16) & 0xf;
 		b->ip6h.flow_lbl[1] = (conn->sock >> 8) & 0xff;
diff --git a/udp.c b/udp.c
index fb8373be..2fd67925 100644
--- a/udp.c
+++ b/udp.c
@@ -625,6 +625,7 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 {
 	struct udp6_l2_buf_t *b = &udp6_l2_buf[n];
 	const struct in6_addr *src, *dst;
+	uint16_t payload_len;
 	in_port_t src_port;
 	size_t ip_len;
 
@@ -634,7 +635,8 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 
 	ip_len = udp6_l2_mh_sock[n].msg_len + sizeof(b->ip6h) + sizeof(b->uh);
 
-	b->ip6h.payload_len = htons(udp6_l2_mh_sock[n].msg_len + sizeof(b->uh));
+	payload_len = udp6_l2_mh_sock[n].msg_len + sizeof(b->uh);
+	b->ip6h.payload_len = htons(payload_len);
 
 	if (IN6_IS_ADDR_LINKLOCAL(src)) {
 		dst = &c->ip6.addr_ll_seen;
@@ -670,17 +672,17 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 	}
 	b->ip6h.daddr = *dst;
 	b->ip6h.saddr = *src;
+	b->ip6h.version = 6;
+	b->ip6h.nexthdr = IPPROTO_UDP;
+	b->ip6h.hop_limit = 255;
 
 	b->uh.source = b->s_in6.sin6_port;
 	b->uh.dest = htons(dstport);
 	b->uh.len = b->ip6h.payload_len;
-
-	b->ip6h.hop_limit = IPPROTO_UDP;
-	b->ip6h.version = b->ip6h.nexthdr = b->uh.check = 0;
-	b->uh.check = csum(&b->ip6h, ip_len, 0);
-	b->ip6h.version = 6;
-	b->ip6h.nexthdr = IPPROTO_UDP;
-	b->ip6h.hop_limit = 255;
+	b->uh.check = 0;
+	b->uh.check = csum(&b->uh, payload_len,
+			   proto_ipv6_header_psum(payload_len, IPPROTO_UDP,
+						  src, dst));
 
 	return tap_iov_len(c, &b->taph, ip_len);
 }
-- 
@@ -625,6 +625,7 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 {
 	struct udp6_l2_buf_t *b = &udp6_l2_buf[n];
 	const struct in6_addr *src, *dst;
+	uint16_t payload_len;
 	in_port_t src_port;
 	size_t ip_len;
 
@@ -634,7 +635,8 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 
 	ip_len = udp6_l2_mh_sock[n].msg_len + sizeof(b->ip6h) + sizeof(b->uh);
 
-	b->ip6h.payload_len = htons(udp6_l2_mh_sock[n].msg_len + sizeof(b->uh));
+	payload_len = udp6_l2_mh_sock[n].msg_len + sizeof(b->uh);
+	b->ip6h.payload_len = htons(payload_len);
 
 	if (IN6_IS_ADDR_LINKLOCAL(src)) {
 		dst = &c->ip6.addr_ll_seen;
@@ -670,17 +672,17 @@ static size_t udp_update_hdr6(const struct ctx *c, int n, in_port_t dstport,
 	}
 	b->ip6h.daddr = *dst;
 	b->ip6h.saddr = *src;
+	b->ip6h.version = 6;
+	b->ip6h.nexthdr = IPPROTO_UDP;
+	b->ip6h.hop_limit = 255;
 
 	b->uh.source = b->s_in6.sin6_port;
 	b->uh.dest = htons(dstport);
 	b->uh.len = b->ip6h.payload_len;
-
-	b->ip6h.hop_limit = IPPROTO_UDP;
-	b->ip6h.version = b->ip6h.nexthdr = b->uh.check = 0;
-	b->uh.check = csum(&b->ip6h, ip_len, 0);
-	b->ip6h.version = 6;
-	b->ip6h.nexthdr = IPPROTO_UDP;
-	b->ip6h.hop_limit = 255;
+	b->uh.check = 0;
+	b->uh.check = csum(&b->uh, payload_len,
+			   proto_ipv6_header_psum(payload_len, IPPROTO_UDP,
+						  src, dst));
 
 	return tap_iov_len(c, &b->taph, ip_len);
 }
-- 
2.44.0

[PATCH v2 8/9] tap: make tap_update_mac() generic

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

Use ethhdr rather than tap_hdr.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-ID: <20240303135114.1023026-9-lvivier@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 tap.c | 10 +++++-----
 tap.h |  2 +-
 tcp.c |  8 ++++----
 udp.c |  4 ++--
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/tap.c b/tap.c
index f971461c..c7b93726 100644
--- a/tap.c
+++ b/tap.c
@@ -419,18 +419,18 @@ size_t tap_send_frames(const struct ctx *c, const struct iovec *iov, size_t n)
 }
 
 /**
- * tap_update_mac() - Update tap L2 header with new Ethernet addresses
- * @taph:	Tap headers to update
+ * eth_update_mac() - Update tap L2 header with new Ethernet addresses
+ * @eh:		Ethernet headers to update
  * @eth_d:	Ethernet destination address, NULL if unchanged
  * @eth_s:	Ethernet source address, NULL if unchanged
  */
-void tap_update_mac(struct tap_hdr *taph,
+void eth_update_mac(struct ethhdr *eh,
 		    const unsigned char *eth_d, const unsigned char *eth_s)
 {
 	if (eth_d)
-		memcpy(taph->eh.h_dest, eth_d, sizeof(taph->eh.h_dest));
+		memcpy(eh->h_dest, eth_d, sizeof(eh->h_dest));
 	if (eth_s)
-		memcpy(taph->eh.h_source, eth_s, sizeof(taph->eh.h_source));
+		memcpy(eh->h_source, eth_s, sizeof(eh->h_source));
 }
 
 PACKET_POOL_DECL(pool_l4, UIO_MAXIOV, pkt_buf);
diff --git a/tap.h b/tap.h
index 466d9146..437b9aa2 100644
--- a/tap.h
+++ b/tap.h
@@ -74,7 +74,7 @@ void tap_icmp6_send(const struct ctx *c,
 		    const void *in, size_t len);
 int tap_send(const struct ctx *c, const void *data, size_t len);
 size_t tap_send_frames(const struct ctx *c, const struct iovec *iov, size_t n);
-void tap_update_mac(struct tap_hdr *taph,
+void eth_update_mac(struct ethhdr *eh,
 		    const unsigned char *eth_d, const unsigned char *eth_s);
 void tap_listen_handler(struct ctx *c, uint32_t events);
 void tap_handler_pasta(struct ctx *c, uint32_t events,
diff --git a/tcp.c b/tcp.c
index a7156ee1..db42d535 100644
--- a/tcp.c
+++ b/tcp.c
@@ -981,10 +981,10 @@ void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
 		struct tcp4_l2_buf_t *b4 = &tcp4_l2_buf[i];
 		struct tcp6_l2_buf_t *b6 = &tcp6_l2_buf[i];
 
-		tap_update_mac(&b4->taph, eth_d, eth_s);
-		tap_update_mac(&b6->taph, eth_d, eth_s);
-		tap_update_mac(&b4f->taph, eth_d, eth_s);
-		tap_update_mac(&b6f->taph, eth_d, eth_s);
+		eth_update_mac(&b4->taph.eh, eth_d, eth_s);
+		eth_update_mac(&b6->taph.eh, eth_d, eth_s);
+		eth_update_mac(&b4f->taph.eh, eth_d, eth_s);
+		eth_update_mac(&b6f->taph.eh, eth_d, eth_s);
 	}
 }
 
diff --git a/udp.c b/udp.c
index 2fd67925..1f46afb2 100644
--- a/udp.c
+++ b/udp.c
@@ -288,8 +288,8 @@ void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
 		struct udp4_l2_buf_t *b4 = &udp4_l2_buf[i];
 		struct udp6_l2_buf_t *b6 = &udp6_l2_buf[i];
 
-		tap_update_mac(&b4->taph, eth_d, eth_s);
-		tap_update_mac(&b6->taph, eth_d, eth_s);
+		eth_update_mac(&b4->taph.eh, eth_d, eth_s);
+		eth_update_mac(&b6->taph.eh, eth_d, eth_s);
 	}
 }
 
-- 
@@ -288,8 +288,8 @@ void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
 		struct udp4_l2_buf_t *b4 = &udp4_l2_buf[i];
 		struct udp6_l2_buf_t *b6 = &udp6_l2_buf[i];
 
-		tap_update_mac(&b4->taph, eth_d, eth_s);
-		tap_update_mac(&b6->taph, eth_d, eth_s);
+		eth_update_mac(&b4->taph.eh, eth_d, eth_s);
+		eth_update_mac(&b6->taph.eh, eth_d, eth_s);
 	}
 }
 
-- 
2.44.0

[PATCH v2 9/9] tcp: Introduce tcp_fill_headers4()/tcp_fill_headers6()

[David Gibson]

From: Laurent Vivier <lvivier@redhat.com>

Replace the macro SET_TCP_HEADER_COMMON_V4_V6() by a new function
tcp_fill_header().

Move IPv4 and IPv6 code from tcp_l2_buf_fill_headers() to
tcp_fill_headers4() and tcp_fill_headers6()

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-ID: <20240303135114.1023026-10-lvivier@redhat.com>
[dwg: Correct commit message with new function names]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 tcp.c | 156 +++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 106 insertions(+), 50 deletions(-)

diff --git a/tcp.c b/tcp.c
index db42d535..d5eedf4d 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1327,6 +1327,108 @@ void tcp_defer_handler(struct ctx *c)
 	tcp_l2_data_buf_flush(c);
 }
 
+/**
+ * tcp_fill_header() - Fill the TCP header fields for a given TCP segment.
+ *
+ * @th:		Pointer to the TCP header structure
+ * @conn:	Pointer to the TCP connection structure
+ * @seq:	Sequence number
+ */
+static void tcp_fill_header(struct tcphdr *th,
+			       const struct tcp_tap_conn *conn, uint32_t seq)
+{
+	th->source = htons(conn->fport);
+	th->dest = htons(conn->eport);
+	th->seq = htonl(seq);
+	th->ack_seq = htonl(conn->seq_ack_to_tap);
+	if (conn->events & ESTABLISHED)	{
+		th->window = htons(conn->wnd_to_tap);
+	} else {
+		unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap;
+
+		th->window = htons(MIN(wnd, USHRT_MAX));
+	}
+}
+
+/**
+ * tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
+ * @c:		Execution context
+ * @conn:	Connection pointer
+ * @iph:	Pointer to IPv4 header
+ * @th:		Pointer to TCP header
+ * @plen:	Payload length (including TCP header options)
+ * @check:	Checksum, if already known
+ * @seq:	Sequence number for this segment
+ *
+ * Return: The total length of the IPv4 packet, host order
+ */
+static size_t tcp_fill_headers4(const struct ctx *c,
+				const struct tcp_tap_conn *conn,
+				struct iphdr *iph, struct tcphdr *th,
+				size_t plen, const uint16_t *check,
+				uint32_t seq)
+{
+	size_t ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
+	const struct in_addr *a4 = inany_v4(&conn->faddr);
+
+	ASSERT(a4);
+
+	iph->tot_len = htons(ip_len);
+	iph->saddr = a4->s_addr;
+	iph->daddr = c->ip4.addr_seen.s_addr;
+
+	iph->check = check ? *check :
+			     csum_ip4_header(iph->tot_len, IPPROTO_TCP,
+					     *a4, c->ip4.addr_seen);
+
+	tcp_fill_header(th, conn, seq);
+
+	tcp_update_check_tcp4(iph, th);
+
+	return ip_len;
+}
+
+/**
+ * tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
+ * @c:		Execution context
+ * @conn:	Connection pointer
+ * @ip6h:	Pointer to IPv6 header
+ * @th:		Pointer to TCP header
+ * @plen:	Payload length (including TCP header options)
+ * @check:	Checksum, if already known
+ * @seq:	Sequence number for this segment
+ *
+ * Return: The total length of the IPv6 packet, host order
+ */
+static size_t tcp_fill_headers6(const struct ctx *c,
+				const struct tcp_tap_conn *conn,
+				struct ipv6hdr *ip6h, struct tcphdr *th,
+				size_t plen, uint32_t seq)
+{
+	size_t ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
+
+	ip6h->payload_len = htons(plen + sizeof(struct tcphdr));
+	ip6h->saddr = conn->faddr.a6;
+	if (IN6_IS_ADDR_LINKLOCAL(&ip6h->saddr))
+		ip6h->daddr = c->ip6.addr_ll_seen;
+	else
+		ip6h->daddr = c->ip6.addr_seen;
+
+	ip6h->hop_limit = 255;
+	ip6h->version = 6;
+	ip6h->nexthdr = IPPROTO_TCP;
+
+	ip6h->flow_lbl[0] = (conn->sock >> 16) & 0xf;
+	ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
+	ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
+
+	tcp_fill_header(th, conn, seq);
+
+	tcp_update_check_tcp6(ip6h, th);
+
+	return ip_len;
+}
+
 /**
  * tcp_l2_buf_fill_headers() - Fill 802.3, IP, TCP headers in pre-cooked buffers
  * @c:		Execution context
@@ -1346,67 +1448,21 @@ static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
 	const struct in_addr *a4 = inany_v4(&conn->faddr);
 	size_t ip_len, tlen;
 
-#define SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq)			\
-do {									\
-	b->th.source = htons(conn->fport);				\
-	b->th.dest = htons(conn->eport);				\
-	b->th.seq = htonl(seq);						\
-	b->th.ack_seq = htonl(conn->seq_ack_to_tap);			\
-	if (conn->events & ESTABLISHED)	{				\
-		b->th.window = htons(conn->wnd_to_tap);			\
-	} else {							\
-		unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap;	\
-									\
-		b->th.window = htons(MIN(wnd, USHRT_MAX));		\
-	}								\
-} while (0)
-
 	if (a4) {
 		struct tcp4_l2_buf_t *b = (struct tcp4_l2_buf_t *)p;
 
-		ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
-		b->iph.tot_len = htons(ip_len);
-		b->iph.saddr = a4->s_addr;
-		b->iph.daddr = c->ip4.addr_seen.s_addr;
-
-		b->iph.check = check ? *check :
-			       csum_ip4_header(b->iph.tot_len, IPPROTO_TCP,
-					       *a4, c->ip4.addr_seen);
-
-		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
-
-		tcp_update_check_tcp4(&b->iph, &b->th);
+		ip_len = tcp_fill_headers4(c, conn, &b->iph, &b->th, plen,
+					   check, seq);
 
 		tlen = tap_iov_len(c, &b->taph, ip_len);
 	} else {
 		struct tcp6_l2_buf_t *b = (struct tcp6_l2_buf_t *)p;
 
-		ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
-
-		b->ip6h.payload_len = htons(plen + sizeof(struct tcphdr));
-		b->ip6h.saddr = conn->faddr.a6;
-		if (IN6_IS_ADDR_LINKLOCAL(&b->ip6h.saddr))
-			b->ip6h.daddr = c->ip6.addr_ll_seen;
-		else
-			b->ip6h.daddr = c->ip6.addr_seen;
-
-		memset(b->ip6h.flow_lbl, 0, 3);
-
-		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
-
-		tcp_update_check_tcp6(&b->ip6h, &b->th);
-
-		b->ip6h.hop_limit = 255;
-		b->ip6h.version = 6;
-		b->ip6h.nexthdr = IPPROTO_TCP;
-
-		b->ip6h.flow_lbl[0] = (conn->sock >> 16) & 0xf;
-		b->ip6h.flow_lbl[1] = (conn->sock >> 8) & 0xff;
-		b->ip6h.flow_lbl[2] = (conn->sock >> 0) & 0xff;
+		ip_len = tcp_fill_headers6(c, conn, &b->ip6h, &b->th, plen,
+					   seq);
 
 		tlen = tap_iov_len(c, &b->taph, ip_len);
 	}
-#undef SET_TCP_HEADER_COMMON_V4_V6
 
 	return tlen;
 }
-- 
@@ -1327,6 +1327,108 @@ void tcp_defer_handler(struct ctx *c)
 	tcp_l2_data_buf_flush(c);
 }
 
+/**
+ * tcp_fill_header() - Fill the TCP header fields for a given TCP segment.
+ *
+ * @th:		Pointer to the TCP header structure
+ * @conn:	Pointer to the TCP connection structure
+ * @seq:	Sequence number
+ */
+static void tcp_fill_header(struct tcphdr *th,
+			       const struct tcp_tap_conn *conn, uint32_t seq)
+{
+	th->source = htons(conn->fport);
+	th->dest = htons(conn->eport);
+	th->seq = htonl(seq);
+	th->ack_seq = htonl(conn->seq_ack_to_tap);
+	if (conn->events & ESTABLISHED)	{
+		th->window = htons(conn->wnd_to_tap);
+	} else {
+		unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap;
+
+		th->window = htons(MIN(wnd, USHRT_MAX));
+	}
+}
+
+/**
+ * tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
+ * @c:		Execution context
+ * @conn:	Connection pointer
+ * @iph:	Pointer to IPv4 header
+ * @th:		Pointer to TCP header
+ * @plen:	Payload length (including TCP header options)
+ * @check:	Checksum, if already known
+ * @seq:	Sequence number for this segment
+ *
+ * Return: The total length of the IPv4 packet, host order
+ */
+static size_t tcp_fill_headers4(const struct ctx *c,
+				const struct tcp_tap_conn *conn,
+				struct iphdr *iph, struct tcphdr *th,
+				size_t plen, const uint16_t *check,
+				uint32_t seq)
+{
+	size_t ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
+	const struct in_addr *a4 = inany_v4(&conn->faddr);
+
+	ASSERT(a4);
+
+	iph->tot_len = htons(ip_len);
+	iph->saddr = a4->s_addr;
+	iph->daddr = c->ip4.addr_seen.s_addr;
+
+	iph->check = check ? *check :
+			     csum_ip4_header(iph->tot_len, IPPROTO_TCP,
+					     *a4, c->ip4.addr_seen);
+
+	tcp_fill_header(th, conn, seq);
+
+	tcp_update_check_tcp4(iph, th);
+
+	return ip_len;
+}
+
+/**
+ * tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
+ * @c:		Execution context
+ * @conn:	Connection pointer
+ * @ip6h:	Pointer to IPv6 header
+ * @th:		Pointer to TCP header
+ * @plen:	Payload length (including TCP header options)
+ * @check:	Checksum, if already known
+ * @seq:	Sequence number for this segment
+ *
+ * Return: The total length of the IPv6 packet, host order
+ */
+static size_t tcp_fill_headers6(const struct ctx *c,
+				const struct tcp_tap_conn *conn,
+				struct ipv6hdr *ip6h, struct tcphdr *th,
+				size_t plen, uint32_t seq)
+{
+	size_t ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
+
+	ip6h->payload_len = htons(plen + sizeof(struct tcphdr));
+	ip6h->saddr = conn->faddr.a6;
+	if (IN6_IS_ADDR_LINKLOCAL(&ip6h->saddr))
+		ip6h->daddr = c->ip6.addr_ll_seen;
+	else
+		ip6h->daddr = c->ip6.addr_seen;
+
+	ip6h->hop_limit = 255;
+	ip6h->version = 6;
+	ip6h->nexthdr = IPPROTO_TCP;
+
+	ip6h->flow_lbl[0] = (conn->sock >> 16) & 0xf;
+	ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
+	ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
+
+	tcp_fill_header(th, conn, seq);
+
+	tcp_update_check_tcp6(ip6h, th);
+
+	return ip_len;
+}
+
 /**
  * tcp_l2_buf_fill_headers() - Fill 802.3, IP, TCP headers in pre-cooked buffers
  * @c:		Execution context
@@ -1346,67 +1448,21 @@ static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
 	const struct in_addr *a4 = inany_v4(&conn->faddr);
 	size_t ip_len, tlen;
 
-#define SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq)			\
-do {									\
-	b->th.source = htons(conn->fport);				\
-	b->th.dest = htons(conn->eport);				\
-	b->th.seq = htonl(seq);						\
-	b->th.ack_seq = htonl(conn->seq_ack_to_tap);			\
-	if (conn->events & ESTABLISHED)	{				\
-		b->th.window = htons(conn->wnd_to_tap);			\
-	} else {							\
-		unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap;	\
-									\
-		b->th.window = htons(MIN(wnd, USHRT_MAX));		\
-	}								\
-} while (0)
-
 	if (a4) {
 		struct tcp4_l2_buf_t *b = (struct tcp4_l2_buf_t *)p;
 
-		ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
-		b->iph.tot_len = htons(ip_len);
-		b->iph.saddr = a4->s_addr;
-		b->iph.daddr = c->ip4.addr_seen.s_addr;
-
-		b->iph.check = check ? *check :
-			       csum_ip4_header(b->iph.tot_len, IPPROTO_TCP,
-					       *a4, c->ip4.addr_seen);
-
-		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
-
-		tcp_update_check_tcp4(&b->iph, &b->th);
+		ip_len = tcp_fill_headers4(c, conn, &b->iph, &b->th, plen,
+					   check, seq);
 
 		tlen = tap_iov_len(c, &b->taph, ip_len);
 	} else {
 		struct tcp6_l2_buf_t *b = (struct tcp6_l2_buf_t *)p;
 
-		ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
-
-		b->ip6h.payload_len = htons(plen + sizeof(struct tcphdr));
-		b->ip6h.saddr = conn->faddr.a6;
-		if (IN6_IS_ADDR_LINKLOCAL(&b->ip6h.saddr))
-			b->ip6h.daddr = c->ip6.addr_ll_seen;
-		else
-			b->ip6h.daddr = c->ip6.addr_seen;
-
-		memset(b->ip6h.flow_lbl, 0, 3);
-
-		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
-
-		tcp_update_check_tcp6(&b->ip6h, &b->th);
-
-		b->ip6h.hop_limit = 255;
-		b->ip6h.version = 6;
-		b->ip6h.nexthdr = IPPROTO_TCP;
-
-		b->ip6h.flow_lbl[0] = (conn->sock >> 16) & 0xf;
-		b->ip6h.flow_lbl[1] = (conn->sock >> 8) & 0xff;
-		b->ip6h.flow_lbl[2] = (conn->sock >> 0) & 0xff;
+		ip_len = tcp_fill_headers6(c, conn, &b->ip6h, &b->th, plen,
+					   seq);
 
 		tlen = tap_iov_len(c, &b->taph, ip_len);
 	}
-#undef SET_TCP_HEADER_COMMON_V4_V6
 
 	return tlen;
 }
-- 
2.44.0

Re: [PATCH v2 0/9] vhost-user part 1, v6

[Stefano Brivio]

On Wed,  6 Mar 2024 16:58:29 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> When I rebased by own code, I hit the problems Stefano mentioned with
> static checker regressions in the vhost-user series.  Laurent's most
> recent vhost-user part 1 series, but with fixes applied for the
> cppcheck and clang-tidy regressions introduced.
> 
> Changes since 'v5 + static checker fixes'
>  * Added my own alteration notes and S-o-b
> Changes since v5:
>  * Fixed a number of static checker regressions

Applied.

-- 
Stefano