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From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v3 04/20] inany: Introduce union sockaddr_inany
Date: Wed, 28 Feb 2024 22:25:04 +1100	[thread overview]
Message-ID: <20240228112520.2078220-5-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20240228112520.2078220-1-david@gibson.dropbear.id.au>

There are a number of places where we want to handle either a
sockaddr_in or a sockaddr_in6.  In some of those we use a void *,
which works ok and matches some standard library interfaces, but
doesn't give a signature level hint that we're dealing with only
sockaddr_in or sockaddr_in6, not (say) sockaddr_un or another type of
socket address.  Other places we use a sockaddr_storage, which also
works, but has the same problem in addition to allocating more on the
stack than we need to.

Introduce union sockaddr_inany to explictly handle this case: it has
variants for sockaddr_in and sockaddr_in6.  Use it in a number of
places where it's easy to do so.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 icmp.c       | 18 ++++++------------
 inany.h      | 33 +++++++++++++++++++++------------
 tcp.c        | 11 +++++------
 tcp_splice.c |  2 +-
 tcp_splice.h |  3 ++-
 5 files changed, 35 insertions(+), 32 deletions(-)

diff --git a/icmp.c b/icmp.c
index faa38c81..fb2fcafc 100644
--- a/icmp.c
+++ b/icmp.c
@@ -36,6 +36,8 @@
 #include "passt.h"
 #include "tap.h"
 #include "log.h"
+#include "siphash.h"
+#include "inany.h"
 #include "icmp.h"
 
 #define ICMP_ECHO_TIMEOUT	60 /* s, timeout for ICMP socket activity */
@@ -67,13 +69,9 @@ void icmp_sock_handler(const struct ctx *c, sa_family_t af, union epoll_ref ref)
 	struct icmp_id_sock *const id_sock = af == AF_INET
 		? &icmp_id_map[V4][ref.icmp.id] : &icmp_id_map[V6][ref.icmp.id];
 	const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
-	char buf[USHRT_MAX];
-	union {
-		struct sockaddr sa;
-		struct sockaddr_in sa4;
-		struct sockaddr_in6 sa6;
-	} sr;
+	union sockaddr_inany sr;
 	socklen_t sl = sizeof(sr);
+	char buf[USHRT_MAX];
 	uint16_t seq;
 	ssize_t n;
 
@@ -86,7 +84,7 @@ void icmp_sock_handler(const struct ctx *c, sa_family_t af, union epoll_ref ref)
 		     pname, strerror(errno));
 		return;
 	}
-	if (sr.sa.sa_family != af)
+	if (sr.sa_family != af)
 		goto unexpected;
 
 	if (af == AF_INET) {
@@ -214,11 +212,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
 		     const struct pool *p, const struct timespec *now)
 {
 	const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
-	union {
-		struct sockaddr sa;
-		struct sockaddr_in sa4;
-		struct sockaddr_in6 sa6;
-	} sa = { .sa.sa_family = af };
+	union sockaddr_inany sa = { .sa_family = af };
 	const socklen_t sl = af == AF_INET ? sizeof(sa.sa4) : sizeof(sa.sa6);
 	struct icmp_id_sock *id_sock;
 	uint16_t id, seq;
diff --git a/inany.h b/inany.h
index 84e82b0f..407690e2 100644
--- a/inany.h
+++ b/inany.h
@@ -9,6 +9,8 @@
 #ifndef INANY_H
 #define INANY_H
 
+struct siphash_state;
+
 /** union inany_addr - Represents either an IPv4 or IPv6 address
  * @a6:			Address as an IPv6 address, may be IPv4-mapped
  * @v4mapped.zero:	All zero-bits for an IPv4 address
@@ -41,6 +43,19 @@ extern const union inany_addr inany_any4;
 #define in4addr_loopback	(inany_loopback4.v4mapped.a4)
 #define in4addr_any		(inany_any4.v4mapped.a4)
 
+/** union sockaddr_inany - Either a sockaddr_in or a sockaddr_in6
+ * @sa_family:	Address family, AF_INET or AF_INET6
+ * @sa:		Plain struct sockaddr (useful to avoid casts)
+ * @sa4:	IPv4 socket address, valid if sa_family == AF_INET
+ * @sa6:	IPv6 socket address, valid if sa_family == AF_INET6
+ */
+union sockaddr_inany {
+	sa_family_t		sa_family;
+	struct sockaddr		sa;
+	struct sockaddr_in	sa4;
+	struct sockaddr_in6	sa6;
+};
+
 /** inany_v4 - Extract IPv4 address, if present, from IPv[46] address
  * @addr:	IPv4 or IPv6 address
  *
@@ -137,23 +152,17 @@ static inline void inany_from_af(union inany_addr *aa,
 /** inany_from_sockaddr - Extract IPv[46] address and port number from sockaddr
  * @aa:		Pointer to store IPv[46] address
  * @port:	Pointer to store port number, host order
- * @addr:	struct sockaddr_in (IPv4) or struct sockaddr_in6 (IPv6)
+ * @addr:	AF_INET or AF_INET6 socket address
  */
 static inline void inany_from_sockaddr(union inany_addr *aa, in_port_t *port,
-				       const void *addr)
+				       const union sockaddr_inany *sa)
 {
-	const struct sockaddr *sa = (const struct sockaddr *)addr;
-
 	if (sa->sa_family == AF_INET6) {
-		struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa;
-
-		inany_from_af(aa, AF_INET6, &sa6->sin6_addr);
-		*port = ntohs(sa6->sin6_port);
+		inany_from_af(aa, AF_INET6, &sa->sa6.sin6_addr);
+		*port = ntohs(sa->sa6.sin6_port);
 	} else if (sa->sa_family == AF_INET) {
-		struct sockaddr_in *sa4 = (struct sockaddr_in *)sa;
-
-		inany_from_af(aa, AF_INET, &sa4->sin_addr);
-		*port = ntohs(sa4->sin_port);
+		inany_from_af(aa, AF_INET, &sa->sa4.sin_addr);
+		*port = ntohs(sa->sa4.sin_port);
 	} else {
 		/* Not valid to call with other address families */
 		ASSERT(0);
diff --git a/tcp.c b/tcp.c
index dbe787b0..53502b1e 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2689,7 +2689,7 @@ static void tcp_snat_inbound(const struct ctx *c, union inany_addr *addr)
 static void tcp_tap_conn_from_sock(struct ctx *c,
 				   union tcp_listen_epoll_ref ref,
 				   struct tcp_tap_conn *conn, int s,
-				   const struct sockaddr *sa,
+				   const union sockaddr_inany *sa,
 				   const struct timespec *now)
 {
 	conn->f.type = FLOW_TCP;
@@ -2725,7 +2725,7 @@ static void tcp_tap_conn_from_sock(struct ctx *c,
 void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 			const struct timespec *now)
 {
-	struct sockaddr_storage sa;
+	union sockaddr_inany sa;
 	socklen_t sl = sizeof(sa);
 	union flow *flow;
 	int s;
@@ -2733,17 +2733,16 @@ void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
 	if (c->no_tcp || !(flow = flow_alloc()))
 		return;
 
-	s = accept4(ref.fd, (struct sockaddr *)&sa, &sl, SOCK_NONBLOCK);
+	s = accept4(ref.fd, &sa.sa, &sl, SOCK_NONBLOCK);
 	if (s < 0)
 		goto cancel;
 
 	if (c->mode == MODE_PASTA &&
 	    tcp_splice_conn_from_sock(c, ref.tcp_listen, &flow->tcp_splice,
-				      s, (struct sockaddr *)&sa))
+				      s, &sa))
 		return;
 
-	tcp_tap_conn_from_sock(c, ref.tcp_listen, &flow->tcp, s,
-			       (struct sockaddr *)&sa, now);
+	tcp_tap_conn_from_sock(c, ref.tcp_listen, &flow->tcp, s, &sa, now);
 	return;
 
 cancel:
diff --git a/tcp_splice.c b/tcp_splice.c
index cdc09a4c..beb2fcb4 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -447,7 +447,7 @@ static int tcp_splice_new(const struct ctx *c, struct tcp_splice_conn *conn,
 bool tcp_splice_conn_from_sock(const struct ctx *c,
 			       union tcp_listen_epoll_ref ref,
 			       struct tcp_splice_conn *conn, int s,
-			       const struct sockaddr *sa)
+			       const union sockaddr_inany *sa)
 {
 	union inany_addr aany;
 	in_port_t port;
diff --git a/tcp_splice.h b/tcp_splice.h
index 18193e4e..20f41b39 100644
--- a/tcp_splice.h
+++ b/tcp_splice.h
@@ -7,13 +7,14 @@
 #define TCP_SPLICE_H
 
 struct tcp_splice_conn;
+union sockaddr_inany;
 
 void tcp_splice_sock_handler(struct ctx *c, union epoll_ref ref,
 			     uint32_t events);
 bool tcp_splice_conn_from_sock(const struct ctx *c,
 			       union tcp_listen_epoll_ref ref,
 			       struct tcp_splice_conn *conn, int s,
-			       const struct sockaddr *sa);
+			       const union sockaddr_inany *sa);
 void tcp_splice_init(struct ctx *c);
 
 #endif /* TCP_SPLICE_H */
-- 
@@ -7,13 +7,14 @@
 #define TCP_SPLICE_H
 
 struct tcp_splice_conn;
+union sockaddr_inany;
 
 void tcp_splice_sock_handler(struct ctx *c, union epoll_ref ref,
 			     uint32_t events);
 bool tcp_splice_conn_from_sock(const struct ctx *c,
 			       union tcp_listen_epoll_ref ref,
 			       struct tcp_splice_conn *conn, int s,
-			       const struct sockaddr *sa);
+			       const union sockaddr_inany *sa);
 void tcp_splice_init(struct ctx *c);
 
 #endif /* TCP_SPLICE_H */
-- 
2.43.2


  parent reply	other threads:[~2024-02-28 11:25 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-28 11:25 [PATCH v3 00/20] More flow table preliminaries: address handling improvements David Gibson
2024-02-28 11:25 ` [PATCH v3 01/20] inany: Helper to test for various address types David Gibson
2024-02-28 11:25 ` [PATCH v3 02/20] inany: Add inany_ntop() helper David Gibson
2024-02-28 11:25 ` [PATCH v3 03/20] inany: Provide more conveniently typed constants for special addresses David Gibson
2024-02-28 11:25 ` David Gibson [this message]
2024-02-28 11:25 ` [PATCH v3 05/20] util: Allow IN4_IS_* macros to operate on untyped addresses David Gibson
2024-02-28 11:25 ` [PATCH v3 06/20] tcp, udp: Don't precompute port remappings in epoll references David Gibson
2024-02-28 11:25 ` [PATCH v3 07/20] flow: Add helper to determine a flow's protocol David Gibson
2024-02-28 11:25 ` [PATCH v3 08/20] tcp_splice: Simplify clean up logic David Gibson
2024-02-28 11:25 ` [PATCH v3 09/20] tcp_splice: Don't use flow_trace() before setting flow type David Gibson
2024-02-28 11:25 ` [PATCH v3 10/20] flow: Clarify flow entry life cycle, introduce uniform logging David Gibson
2024-02-28 11:25 ` [PATCH v3 11/20] tcp_splice: More specific variable names in new splice path David Gibson
2024-02-28 11:25 ` [PATCH v3 12/20] tcp_splice: Merge tcp_splice_new() into its caller David Gibson
2024-02-28 11:25 ` [PATCH v3 13/20] tcp_splice: Make tcp_splice_connect() create its own sockets David Gibson
2024-02-28 11:25 ` [PATCH v3 14/20] tcp_splice: Improve error reporting on connect path David Gibson
2024-02-28 11:25 ` [PATCH v3 15/20] tcp_splice: Improve logic deciding when to splice David Gibson
2024-02-28 11:25 ` [PATCH v3 16/20] tcp, tcp_splice: Parse listening socket epoll ref in tcp_listen_handler() David Gibson
2024-02-28 11:25 ` [PATCH v3 17/20] tcp: Validate TCP endpoint addresses David Gibson
2024-02-28 11:25 ` [PATCH v3 18/20] tap: Disallow loopback addresses on tap interface David Gibson
2024-02-28 11:25 ` [PATCH v3 19/20] port_fwd: Fix copypasta error in port_fwd_scan_udp() comments David Gibson
2024-02-28 11:25 ` [PATCH v3 20/20] fwd: Rename port_fwd.[ch] and their contents David Gibson
2024-02-29 10:53 ` [PATCH v3 00/20] More flow table preliminaries: address handling improvements Stefano Brivio

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