From 9cb6b508157a92bc0c5c0f71d6b3d09a628a0766 Mon Sep 17 00:00:00 2001 From: Jon Maloy Date: Sat, 20 Jul 2024 09:54:53 -0400 Subject: tcp: probe for SO_PEEK_OFF both in tcpv4 and tcp6 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Based on an original patch by Jon Maloy: -- The recently added socket option SO_PEEK_OFF is not supported for TCP/IPv6 sockets. Until we get that support into the kernel we need to test for support in both protocols to set the global 'peek_offset_cap´ to true. -- Compared to the original patch: - only check for SO_PEEK_OFF support for enabled IP versions - use sa_family_t instead of int to pass the address family around Fixes: e63d281871ef ("tcp: leverage support of SO_PEEK_OFF socket option when available") Signed-off-by: Stefano Brivio Reviewed-by: David Gibson --- tcp.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) diff --git a/tcp.c b/tcp.c index 0c66ac8..c031f13 100644 --- a/tcp.c +++ b/tcp.c @@ -2470,6 +2470,29 @@ static void tcp_sock_refill_init(const struct ctx *c) } } +/** + * tcp_probe_peek_offset_cap() - Check if SO_PEEK_OFF is supported by kernel + * @af: Address family, IPv4 or IPv6 + * + * Return: true if supported, false otherwise + */ +bool tcp_probe_peek_offset_cap(sa_family_t af) +{ + bool ret = false; + int s, optv = 0; + + s = socket(af, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP); + if (s < 0) { + warn_perror("Temporary TCP socket creation failed"); + } else { + if (!setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &optv, sizeof(int))) + ret = true; + close(s); + } + + return ret; +} + /** * tcp_init() - Get initial sequence, hash secret, initialise per-socket data * @c: Execution context @@ -2478,9 +2501,6 @@ static void tcp_sock_refill_init(const struct ctx *c) */ int tcp_init(struct ctx *c) { - unsigned int optv = 0; - int s; - ASSERT(!c->no_tcp); if (c->ifi4) @@ -2502,15 +2522,8 @@ int tcp_init(struct ctx *c) NS_CALL(tcp_ns_socks_init, c); } - /* Probe for SO_PEEK_OFF support */ - s = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP); - if (s < 0) { - warn_perror("Temporary TCP socket creation failed"); - } else { - if (!setsockopt(s, SOL_SOCKET, SO_PEEK_OFF, &optv, sizeof(int))) - peek_offset_cap = true; - close(s); - } + peek_offset_cap = (!c->ifi4 || tcp_probe_peek_offset_cap(AF_INET)) && + (!c->ifi6 || tcp_probe_peek_offset_cap(AF_INET6)); info("SO_PEEK_OFF%ssupported", peek_offset_cap ? " " : " not "); return 0; -- cgit v1.2.3