bird/sysdep/linux/sysio.h
Alexander Zubkov 87a02489f3 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.
2022-01-08 19:02:31 +01:00

287 lines
6.1 KiB
C

/*
* BIRD Internet Routing Daemon -- Linux Multicasting and Network Includes
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef IPV6_MINHOPCOUNT
#define IPV6_MINHOPCOUNT 73
#endif
#ifndef IPV6_FREEBIND
#define IPV6_FREEBIND 78
#endif
#ifndef TCP_MD5SIG_EXT
#define TCP_MD5SIG_EXT 32
#endif
#ifndef TCP_MD5SIG_FLAG_PREFIX
#define TCP_MD5SIG_FLAG_PREFIX 1
#endif
/* We redefine the tcp_md5sig structure with different name to avoid collision with older headers */
struct tcp_md5sig_ext {
struct sockaddr_storage tcpm_addr; /* Address associated */
u8 tcpm_flags; /* Extension flags */
u8 tcpm_prefixlen; /* Address prefix */
u16 tcpm_keylen; /* Key length */
u32 __tcpm_pad2; /* Zero */
u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* Key (binary) */
};
/* Linux does not care if sa_len is larger than needed */
#define SA_LEN(x) sizeof(sockaddr)
/*
* Linux IPv4 multicast syscalls
*/
#define INIT_MREQ4(maddr,ifa) \
{ .imr_multiaddr = ipa_to_in4(maddr), .imr_ifindex = ifa->index }
static inline int
sk_setup_multicast4(sock *s)
{
struct ip_mreqn mr = { .imr_ifindex = s->iface->index };
int ttl = s->ttl;
int n = 0;
/* This defines where should we send _outgoing_ multicasts */
if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_IF, &mr, sizeof(mr)) < 0)
ERR("IP_MULTICAST_IF");
if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
ERR("IP_MULTICAST_TTL");
if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_LOOP, &n, sizeof(n)) < 0)
ERR("IP_MULTICAST_LOOP");
return 0;
}
static inline int
sk_join_group4(sock *s, ip_addr maddr)
{
struct ip_mreqn mr = INIT_MREQ4(maddr, s->iface);
if (setsockopt(s->fd, SOL_IP, IP_ADD_MEMBERSHIP, &mr, sizeof(mr)) < 0)
ERR("IP_ADD_MEMBERSHIP");
return 0;
}
static inline int
sk_leave_group4(sock *s, ip_addr maddr)
{
struct ip_mreqn mr = INIT_MREQ4(maddr, s->iface);
if (setsockopt(s->fd, SOL_IP, IP_DROP_MEMBERSHIP, &mr, sizeof(mr)) < 0)
ERR("IP_DROP_MEMBERSHIP");
return 0;
}
/*
* Linux IPv4 packet control messages
*/
/* Mostly similar to standardized IPv6 code */
#define CMSG4_SPACE_PKTINFO CMSG_SPACE(sizeof(struct in_pktinfo))
#define CMSG4_SPACE_TTL CMSG_SPACE(sizeof(int))
static inline int
sk_request_cmsg4_pktinfo(sock *s)
{
int y = 1;
if (setsockopt(s->fd, SOL_IP, IP_PKTINFO, &y, sizeof(y)) < 0)
ERR("IP_PKTINFO");
return 0;
}
static inline int
sk_request_cmsg4_ttl(sock *s)
{
int y = 1;
if (setsockopt(s->fd, SOL_IP, IP_RECVTTL, &y, sizeof(y)) < 0)
ERR("IP_RECVTTL");
return 0;
}
static inline void
sk_process_cmsg4_pktinfo(sock *s, struct cmsghdr *cm)
{
if (cm->cmsg_type == IP_PKTINFO)
{
struct in_pktinfo *pi = (struct in_pktinfo *) CMSG_DATA(cm);
s->laddr = ipa_from_in4(pi->ipi_addr);
s->lifindex = pi->ipi_ifindex;
}
}
static inline void
sk_process_cmsg4_ttl(sock *s, struct cmsghdr *cm)
{
if (cm->cmsg_type == IP_TTL)
s->rcv_ttl = * (int *) CMSG_DATA(cm);
}
static inline void
sk_prepare_cmsgs4(sock *s, struct msghdr *msg, void *cbuf, size_t cbuflen)
{
struct cmsghdr *cm;
struct in_pktinfo *pi;
int controllen = 0;
msg->msg_control = cbuf;
msg->msg_controllen = cbuflen;
cm = CMSG_FIRSTHDR(msg);
cm->cmsg_level = SOL_IP;
cm->cmsg_type = IP_PKTINFO;
cm->cmsg_len = CMSG_LEN(sizeof(*pi));
controllen += CMSG_SPACE(sizeof(*pi));
pi = (struct in_pktinfo *) CMSG_DATA(cm);
pi->ipi_ifindex = s->iface ? s->iface->index : 0;
pi->ipi_spec_dst = ipa_to_in4(s->saddr);
pi->ipi_addr = ipa_to_in4(IPA_NONE);
msg->msg_controllen = controllen;
}
/*
* Miscellaneous Linux socket syscalls
*/
int
sk_set_md5_auth(sock *s, ip_addr local UNUSED, ip_addr remote, int pxlen, struct iface *ifa, const char *passwd, int setkey UNUSED)
{
struct tcp_md5sig_ext md5;
memset(&md5, 0, sizeof(md5));
sockaddr_fill((sockaddr *) &md5.tcpm_addr, s->af, remote, ifa, 0);
if (passwd)
{
int len = strlen(passwd);
if (len > TCP_MD5SIG_MAXKEYLEN)
ERR_MSG("The password for TCP MD5 Signature is too long");
md5.tcpm_keylen = len;
memcpy(&md5.tcpm_key, passwd, len);
}
if (pxlen < 0)
{
if (setsockopt(s->fd, SOL_TCP, TCP_MD5SIG, &md5, sizeof(md5)) < 0)
if (errno == ENOPROTOOPT)
ERR_MSG("Kernel does not support TCP MD5 signatures");
else
ERR("TCP_MD5SIG");
}
else
{
md5.tcpm_flags = TCP_MD5SIG_FLAG_PREFIX;
md5.tcpm_prefixlen = pxlen;
if (setsockopt(s->fd, SOL_TCP, TCP_MD5SIG_EXT, &md5, sizeof(md5)) < 0)
{
if (errno == ENOPROTOOPT)
ERR_MSG("Kernel does not support extended TCP MD5 signatures");
else
ERR("TCP_MD5SIG_EXT");
}
}
return 0;
}
static inline int
sk_set_min_ttl4(sock *s, int ttl)
{
if (setsockopt(s->fd, SOL_IP, IP_MINTTL, &ttl, sizeof(ttl)) < 0)
{
if (errno == ENOPROTOOPT)
ERR_MSG("Kernel does not support IPv4 TTL security");
else
ERR("IP_MINTTL");
}
return 0;
}
static inline int
sk_set_min_ttl6(sock *s, int ttl)
{
if (setsockopt(s->fd, SOL_IPV6, IPV6_MINHOPCOUNT, &ttl, sizeof(ttl)) < 0)
{
if (errno == ENOPROTOOPT)
ERR_MSG("Kernel does not support IPv6 TTL security");
else
ERR("IPV6_MINHOPCOUNT");
}
return 0;
}
static inline int
sk_disable_mtu_disc4(sock *s)
{
int dont = IP_PMTUDISC_DONT;
if (setsockopt(s->fd, SOL_IP, IP_MTU_DISCOVER, &dont, sizeof(dont)) < 0)
ERR("IP_MTU_DISCOVER");
return 0;
}
static inline int
sk_disable_mtu_disc6(sock *s)
{
int dont = IPV6_PMTUDISC_DONT;
if (setsockopt(s->fd, SOL_IPV6, IPV6_MTU_DISCOVER, &dont, sizeof(dont)) < 0)
ERR("IPV6_MTU_DISCOVER");
return 0;
}
int sk_priority_control = 7;
static inline int
sk_set_priority(sock *s, int prio)
{
if (setsockopt(s->fd, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)) < 0)
ERR("SO_PRIORITY");
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;
}