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From: Laurent Vivier <lvivier@redhat.com>
To: passt-dev@passt.top
Cc: Laurent Vivier <lvivier@redhat.com>,
	David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v4 5/8] checksum: use csum_ip4_header() in udp.c and tcp.c
Date: Thu, 29 Feb 2024 17:59:52 +0100	[thread overview]
Message-ID: <20240229165955.829476-6-lvivier@redhat.com> (raw)
In-Reply-To: <20240229165955.829476-1-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>
---

Notes:
    v4:
      - rebase
    
    v3:
      - function parameters provide tot_len, saddr, daddr and protocol
       rather than an iphdr
    
    v2:
      - use csum_ip4_header() from checksum.c
      - use code from tcp.c and udp.c in csum_ip4_header()
      - use "const struct iphfr *", check is not updated by the
        function but by the caller.

 checksum.c | 17 +++++++++++++----
 checksum.h |  3 ++-
 tap.c      |  3 ++-
 tcp.c      | 24 +++---------------------
 udp.c      | 20 ++------------------
 5 files changed, 22 insertions(+), 45 deletions(-)

diff --git a/checksum.c b/checksum.c
index 74e3742bc6f6..511b296a9a80 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
@@ -116,13 +117,21 @@ uint16_t csum_fold(uint32_t sum)
 uint16_t csum(const void *buf, size_t len, uint32_t init);
 
 /**
- * csum_ip4_header() - Calculate and set IPv4 header checksum
+ * csum_ip4_header() - Calculate IPv4 header checksum
  * @ip4h:	IPv4 header
  */
-void csum_ip4_header(struct iphdr *ip4h)
+uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol,
+			 uint32_t saddr, uint32_t 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 >> 16) & 0xffff;
+	sum += saddr & 0xffff;
+	sum += (daddr >> 16) & 0xffff;
+	sum += daddr & 0xffff;
+
+	return ~csum_fold(sum);
 }
 
 /**
diff --git a/checksum.h b/checksum.h
index dfa705a04a24..92db73612b6e 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,
+			 uint32_t saddr, uint32_t 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 d35d8944fc41..d4649f0167ab 100644
--- a/tap.c
+++ b/tap.c
@@ -161,7 +161,8 @@ 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.s_addr, dst.s_addr);
 	return ip4h + 1;
 }
 
diff --git a/tcp.c b/tcp.c
index e0588f92e65f..ea0802c6b102 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,
+					       b->iph.saddr, b->iph.daddr);
 
 		SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
 
diff --git a/udp.c b/udp.c
index 26774df7018c..d517c99dcc69 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,
+				       b->iph.saddr, b->iph.daddr);
 	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,
+				       b->iph.saddr, b->iph.daddr);
 	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));
-- 
2.42.0


  parent reply	other threads:[~2024-02-29 17:00 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-29 16:59 [PATCH v4 0/8] Add vhost-user support to passt (part 1) Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 1/8] pcap: add pcap_iov() Laurent Vivier
2024-02-29 23:16   ` David Gibson
2024-02-29 16:59 ` [PATCH v4 2/8] checksum: align buffers Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 3/8] checksum: add csum_iov() Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 4/8] util: move IP stuff from util.[ch] to ip.[ch] Laurent Vivier
2024-02-29 23:19   ` David Gibson
2024-03-01 12:06     ` Laurent Vivier
2024-02-29 16:59 ` Laurent Vivier [this message]
2024-02-29 23:25   ` [PATCH v4 5/8] checksum: use csum_ip4_header() in udp.c and tcp.c David Gibson
2024-03-01 12:31     ` Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 6/8] checksum: introduce functions to compute the header part checksum for TCP/UDP Laurent Vivier
2024-02-29 23:42   ` David Gibson
2024-02-29 16:59 ` [PATCH v4 7/8] tap: make tap_update_mac() generic Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 8/8] tcp: Introduce ipv4_fill_headers()/ipv6_fill_headers() Laurent Vivier
2024-02-29 23:54   ` David Gibson
2024-03-03 13:50     ` Laurent Vivier

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