IO: Support nonlocal bind in socket interface

Add option to socket interface for nonlocal binding, i.e. binding to an
IP address that is not present on interfaces. This behaviour is enabled
when SKF_FREEBIND socket flag is set. For Linux systems, it is
implemented by IP_FREEBIND socket flag.

Minor changes done by commiter.
This commit is contained in:
Alexander Zubkov 2022-01-08 18:31:56 +01:00 committed by Ondrej Zajicek (work)
parent bcb25084d3
commit 87a02489f3
4 changed files with 30 additions and 0 deletions

View file

@ -123,6 +123,7 @@ extern int sk_priority_control; /* Suggested priority for control traffic, shou
#define SKF_TTL_RX 0x08 /* Report TTL / Hop Limit for RX packets */ #define SKF_TTL_RX 0x08 /* Report TTL / Hop Limit for RX packets */
#define SKF_BIND 0x10 /* Bind datagram socket to given source address */ #define SKF_BIND 0x10 /* Bind datagram socket to given source address */
#define SKF_HIGH_PORT 0x20 /* Choose port from high range if possible */ #define SKF_HIGH_PORT 0x20 /* Choose port from high range if possible */
#define SKF_FREEBIND 0x40 /* Allow socket to bind to a nonlocal address */
#define SKF_THREAD 0x100 /* Socked used in thread, Do not add to main loop */ #define SKF_THREAD 0x100 /* Socked used in thread, Do not add to main loop */
#define SKF_TRUNCATED 0x200 /* Received packet was truncated, set by IO layer */ #define SKF_TRUNCATED 0x200 /* Received packet was truncated, set by IO layer */

View file

@ -271,3 +271,9 @@ sk_set_priority(sock *s, int prio UNUSED)
{ {
ERR_MSG("Socket priority not supported"); ERR_MSG("Socket priority not supported");
} }
static inline int
sk_set_freebind(sock *s)
{
ERR_MSG("Freebind is not supported");
}

View file

@ -10,6 +10,10 @@
#define IPV6_MINHOPCOUNT 73 #define IPV6_MINHOPCOUNT 73
#endif #endif
#ifndef IPV6_FREEBIND
#define IPV6_FREEBIND 78
#endif
#ifndef TCP_MD5SIG_EXT #ifndef TCP_MD5SIG_EXT
#define TCP_MD5SIG_EXT 32 #define TCP_MD5SIG_EXT 32
#endif #endif
@ -266,3 +270,18 @@ sk_set_priority(sock *s, int prio)
return 0; return 0;
} }
static inline int
sk_set_freebind(sock *s)
{
int y = 1;
if (sk_is_ipv4(s))
if (setsockopt(s->fd, SOL_IP, IP_FREEBIND, &y, sizeof(y)) < 0)
ERR("IP_FREEBIND");
if (sk_is_ipv6(s))
if (setsockopt(s->fd, SOL_IPV6, IPV6_FREEBIND, &y, sizeof(y)) < 0)
ERR("IPV6_FREEBIND");
return 0;
}

View file

@ -1436,6 +1436,10 @@ sk_open(sock *s)
if (sk_set_high_port(s) < 0) if (sk_set_high_port(s) < 0)
log(L_WARN "Socket error: %s%#m", s->err); log(L_WARN "Socket error: %s%#m", s->err);
if (s->flags & SKF_FREEBIND)
if (sk_set_freebind(s) < 0)
log(L_WARN "Socket error: %s%#m", s->err);
sockaddr_fill(&sa, s->af, bind_addr, s->iface, bind_port); sockaddr_fill(&sa, s->af, bind_addr, s->iface, bind_port);
if (bind(fd, &sa.sa, SA_LEN(sa)) < 0) if (bind(fd, &sa.sa, SA_LEN(sa)) < 0)
ERR2("bind"); ERR2("bind");