From 6be71641ef3baa8658d031f3624f4481b493bdaf Mon Sep 17 00:00:00 2001 From: "Ondrej Zajicek (work)" Date: Sat, 28 Jul 2018 16:54:06 +0200 Subject: BSD: Use MSG_DONTROUTE for unicast packets on FreeBSD BSD systems cannot use SO_DONTROUTE, because it does not work properly with multicast packets (perhaps it tries to find iface based on multicast group address). But we can use MSG_DONTROUTE sendmsg() flag for unicast packets. Works on FreeBSD, is ignored on OpenBSD and is broken on NetBSD (i guess due to integrated routing table and ARP table). --- lib/ip.h | 3 +++ sysdep/bsd/sysio.h | 5 +++++ sysdep/cf/README | 1 + sysdep/unix/io.c | 8 +++++++- 4 files changed, 16 insertions(+), 1 deletion(-) diff --git a/lib/ip.h b/lib/ip.h index 298b72a7..d876a707 100644 --- a/lib/ip.h +++ b/lib/ip.h @@ -309,6 +309,9 @@ static inline int ip6_is_v4mapped(ip6_addr a) #define ipa_is_link_local(x) 0 #endif +static inline int ip4_is_unicast(ip4_addr a) +{ return _I(a) < 0xe0000000; } + static inline int ipa_classify_net(ip_addr a) { return ipa_zero2(a) ? (IADDR_HOST | SCOPE_UNIVERSE) : ipa_classify(a); } diff --git a/sysdep/bsd/sysio.h b/sysdep/bsd/sysio.h index 9b10e6e8..545276a3 100644 --- a/sysdep/bsd/sysio.h +++ b/sysdep/bsd/sysio.h @@ -12,6 +12,11 @@ #include +#ifdef __FreeBSD__ +/* Should be defined in sysdep/cf/bsd.h, but it is flavor-specific */ +#define CONFIG_DONTROUTE_UNICAST +#endif + #ifdef __NetBSD__ #ifndef IP_RECVTTL diff --git a/sysdep/cf/README b/sysdep/cf/README index e62c3481..9a7a4afa 100644 --- a/sysdep/cf/README +++ b/sysdep/cf/README @@ -11,6 +11,7 @@ CONFIG_MC_PROPER_SRC Multicast packets have source address according to socket s CONFIG_SKIP_MC_BIND Don't call bind on multicast socket (def for *BSD) CONFIG_NO_IFACE_BIND Bind to iface is not available, use workarounds (def for *BSD) CONFIG_UNIX_DONTROUTE Use setsockopts DONTROUTE (undef for *BSD) +CONFIG_DONTROUTE_UNICAST Use MSG_DONTROUTE flag for unicast packets (def for FreeBSD) CONFIG_USE_HDRINCL Use IP_HDRINCL instead of control messages for source address on raw IP sockets. CONFIG_RESTRICTED_PRIVILEGES Implements restricted privileges using drop_uid() diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c index 53a37a50..786c6a56 100644 --- a/sysdep/unix/io.c +++ b/sysdep/unix/io.c @@ -1574,6 +1574,7 @@ sk_sendmsg(sock *s) struct iovec iov = {s->tbuf, s->tpos - s->tbuf}; byte cmsg_buf[CMSG_TX_SPACE]; sockaddr dst; + int flags = 0; sockaddr_fill(&dst, s->af, s->daddr, s->iface, s->dport); @@ -1584,6 +1585,11 @@ sk_sendmsg(sock *s) .msg_iovlen = 1 }; +#ifdef CONFIG_DONTROUTE_UNICAST + if (ipa_is_ip4(s->daddr) && ip4_is_unicast(ipa_to_ip4(s->daddr))) + flags = MSG_DONTROUTE; +#endif + #ifdef CONFIG_USE_HDRINCL byte hdr[20]; struct iovec iov2[2] = { {hdr, 20}, iov }; @@ -1599,7 +1605,7 @@ sk_sendmsg(sock *s) if (s->flags & SKF_PKTINFO) sk_prepare_cmsgs(s, &msg, cmsg_buf, sizeof(cmsg_buf)); - return sendmsg(s->fd, &msg, 0); + return sendmsg(s->fd, &msg, flags); } static inline int -- cgit v1.2.3