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/*
* AF_INET/AF_INET6 socket management
*
* Copyright 2000-2020 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <string.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <haproxy/api.h>
#include <haproxy/sock_inet.h>
#include <haproxy/tools.h>
/* PLEASE NOTE for function below:
* - sock_inet4_* is solely for AF_INET (IPv4)
* - sock_inet6_* is solely for AF_INET6 (IPv6)
* - sock_inet_* is for either
*
* The address family SHOULD always be checked. In some cases a function will
* be used in a situation where the address family is guaranteed (e.g. protocol
* definitions), so the test may be avoided. This special case must then be
* mentioned in the comment before the function definition.
*/
/* determine if the operating system uses IPV6_V6ONLY by default. 0=no, 1=yes.
* It also remains if IPv6 is not enabled/configured.
*/
int sock_inet6_v6only_default = 0;
/* Default TCPv4/TCPv6 MSS settings. -1=unknown. */
int sock_inet_tcp_maxseg_default = -1;
int sock_inet6_tcp_maxseg_default = -1;
/* Compares two AF_INET sockaddr addresses. Returns 0 if they match or non-zero
* if they do not match.
*/
int sock_inet4_addrcmp(const struct sockaddr_storage *a, const struct sockaddr_storage *b)
{
const struct sockaddr_in *a4 = (const struct sockaddr_in *)a;
const struct sockaddr_in *b4 = (const struct sockaddr_in *)b;
if (a->ss_family != b->ss_family)
return -1;
if (a->ss_family != AF_INET)
return -1;
if (a4->sin_port != b4->sin_port)
return -1;
return memcmp(&a4->sin_addr, &b4->sin_addr, sizeof(a4->sin_addr));
}
/* Compares two AF_INET6 sockaddr addresses. Returns 0 if they match or
* non-zero if they do not match.
*/
int sock_inet6_addrcmp(const struct sockaddr_storage *a, const struct sockaddr_storage *b)
{
const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *)a;
const struct sockaddr_in6 *b6 = (const struct sockaddr_in6 *)b;
if (a->ss_family != b->ss_family)
return -1;
if (a->ss_family != AF_INET6)
return -1;
if (a6->sin6_port != b6->sin6_port)
return -1;
return memcmp(&a6->sin6_addr, &b6->sin6_addr, sizeof(a6->sin6_addr));
}
/*
* Retrieves the original destination address for the socket <fd> which must be
* of family AF_INET (not AF_INET6), with <dir> indicating if we're a listener
* (=0) or an initiator (!=0). In the case of a listener, if the original
* destination address was translated, the original address is retrieved. It
* returns 0 in case of success, -1 in case of error. The socket's source
* address is stored in <sa> for <salen> bytes.
*/
int sock_inet_get_dst(int fd, struct sockaddr *sa, socklen_t salen, int dir)
{
if (dir)
return getpeername(fd, sa, &salen);
else {
int ret = getsockname(fd, sa, &salen);
if (ret < 0)
return ret;
#if defined(USE_TPROXY) && defined(SO_ORIGINAL_DST)
/* For TPROXY and Netfilter's NAT, we can retrieve the original
* IPv4 address before DNAT/REDIRECT. We must not do that with
* other families because v6-mapped IPv4 addresses are still
* reported as v4.
*/
if (getsockopt(fd, SOL_IP, SO_ORIGINAL_DST, sa, &salen) == 0)
return 0;
#endif
return ret;
}
}
/* Returns true if the passed FD corresponds to a socket bound with LI_O_FOREIGN
* according to the various supported socket options. The socket's address family
* must be passed in <family>.
*/
int sock_inet_is_foreign(int fd, sa_family_t family)
{
int val __maybe_unused;
socklen_t len __maybe_unused;
switch (family) {
case AF_INET:
#if defined(IP_TRANSPARENT)
val = 0; len = sizeof(val);
if (getsockopt(fd, SOL_IP, IP_TRANSPARENT, &val, &len) == 0 && val)
return 1;
#endif
#if defined(IP_FREEBIND)
val = 0; len = sizeof(val);
if (getsockopt(fd, SOL_IP, IP_FREEBIND, &val, &len) == 0 && val)
return 1;
#endif
#if defined(IP_BINDANY)
val = 0; len = sizeof(val);
if (getsockopt(fd, IPPROTO_IP, IP_BINDANY, &val, &len) == 0 && val)
return 1;
#endif
#if defined(SO_BINDANY)
val = 0; len = sizeof(val);
if (getsockopt(fd, SOL_SOCKET, SO_BINDANY, &val, &len) == 0 && val)
return 1;
#endif
break;
case AF_INET6:
#if defined(IPV6_TRANSPARENT) && defined(SOL_IPV6)
val = 0; len = sizeof(val);
if (getsockopt(fd, SOL_IPV6, IPV6_TRANSPARENT, &val, &len) == 0 && val)
return 1;
#endif
#if defined(IP_FREEBIND)
val = 0; len = sizeof(val);
if (getsockopt(fd, SOL_IP, IP_FREEBIND, &val, &len) == 0 && val)
return 1;
#endif
#if defined(IPV6_BINDANY)
val = 0; len = sizeof(val);
if (getsockopt(fd, IPPROTO_IPV6, IPV6_BINDANY, &val, &len) == 0 && val)
return 1;
#endif
#if defined(SO_BINDANY)
val = 0; len = sizeof(val);
if (getsockopt(fd, SOL_SOCKET, SO_BINDANY, &val, &len) == 0 && val)
return 1;
#endif
break;
}
return 0;
}
static void sock_inet_prepare()
{
int fd, val;
socklen_t len;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd >= 0) {
#ifdef TCP_MAXSEG
/* retrieve the OS' default mss for TCPv4 */
len = sizeof(val);
if (getsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &val, &len) == 0)
sock_inet_tcp_maxseg_default = val;
#endif
close(fd);
}
fd = socket(AF_INET6, SOCK_STREAM, 0);
if (fd >= 0) {
#if defined(IPV6_V6ONLY)
/* retrieve the OS' bindv6only value */
len = sizeof(val);
if (getsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &val, &len) == 0 && val > 0)
sock_inet6_v6only_default = 1;
#endif
#ifdef TCP_MAXSEG
/* retrieve the OS' default mss for TCPv6 */
len = sizeof(val);
if (getsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &val, &len) == 0)
sock_inet6_tcp_maxseg_default = val;
#endif
close(fd);
}
}
INITCALL0(STG_PREPARE, sock_inet_prepare);