miniupnp/miniupnpd/bsd/getroute.c

149 lines
3.8 KiB
C

/* $Id: getroute.c,v 1.12 2015/11/19 11:46:30 nanard Exp $ */
/* MiniUPnP project
* http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
* (c) 2006-2015 Thomas Bernard
* This software is subject to the conditions detailed
* in the LICENCE file provided within the distribution */
#include <stdio.h>
#include <syslog.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#ifdef AF_LINK
#include <net/if_dl.h>
#endif
#include "../config.h"
#include "../upnputils.h"
#ifndef SA_SIZE
#define SA_SIZE(sa) (SA_LEN(sa))
#endif /* SA_SIZE */
int
get_src_for_route_to(const struct sockaddr * dst,
void * src, size_t * src_len,
int * index)
{
int found = 0;
int s;
int l, i;
char * p;
struct sockaddr * sa;
struct {
struct rt_msghdr m_rtm;
char m_space[512];
} m_rtmsg;
#define rtm m_rtmsg.m_rtm
if(dst == NULL)
return -1;
if(dst->sa_len > 0) {
l = dst->sa_len;
} else {
if(dst->sa_family == AF_INET)
l = sizeof(struct sockaddr_in);
else if(dst->sa_family == AF_INET6)
l = sizeof(struct sockaddr_in6);
else {
syslog(LOG_ERR, "unknown address family %d", dst->sa_family);
return -1;
}
}
s = socket(PF_ROUTE, SOCK_RAW, dst->sa_family);
if(s < 0) {
syslog(LOG_ERR, "socket(PF_ROUTE) failed : %m");
return -1;
}
memset(&rtm, 0, sizeof(rtm));
rtm.rtm_type = RTM_GET;
rtm.rtm_flags = RTF_UP;
rtm.rtm_version = RTM_VERSION;
rtm.rtm_seq = 1;
rtm.rtm_addrs = RTA_DST | RTA_IFA | RTA_IFP; /* pass destination address, request source address & interface */
memcpy(m_rtmsg.m_space, dst, l);
((struct sockaddr *)m_rtmsg.m_space)->sa_len = l;
rtm.rtm_msglen = sizeof(struct rt_msghdr) + l;
if(write(s, &m_rtmsg, rtm.rtm_msglen) < 0) {
syslog(LOG_ERR, "write: %m");
close(s);
return -1;
}
do {
l = read(s, &m_rtmsg, sizeof(m_rtmsg));
if(l<0) {
syslog(LOG_ERR, "read: %m");
close(s);
return -1;
}
syslog(LOG_DEBUG, "read l=%d seq=%d pid=%d sizeof(struct rt_msghdr)=%d",
l, rtm.rtm_seq, rtm.rtm_pid, (int)sizeof(struct rt_msghdr));
} while(l > 0 && (rtm.rtm_pid != getpid() || rtm.rtm_seq != 1));
close(s);
if(l <= 0) {
syslog(LOG_WARNING, "no matching ROUTE response message");
return -1;
}
p = m_rtmsg.m_space;
if(rtm.rtm_addrs) {
for(i=1; i<0x8000; i <<= 1) {
if(i & rtm.rtm_addrs) {
char tmp[256] = { 0 };
if(p >= (char *)&m_rtmsg + l) {
syslog(LOG_ERR, "error parsing ROUTE response message");
break;
}
sa = (struct sockaddr *)p;
sockaddr_to_string(sa, tmp, sizeof(tmp));
syslog(LOG_DEBUG, "type=%d sa_len=%d sa_family=%d %s",
i, sa->sa_len, sa->sa_family, tmp);
if(i == RTA_IFA) {
size_t len = 0;
void * paddr = NULL;
if(sa->sa_family == AF_INET) {
paddr = &((struct sockaddr_in *)sa)->sin_addr;
len = sizeof(struct in_addr);
} else if(sa->sa_family == AF_INET6) {
paddr = &((struct sockaddr_in6 *)sa)->sin6_addr;
len = sizeof(struct in6_addr);
}
if(paddr) {
if(src && src_len) {
if(*src_len < len) {
syslog(LOG_WARNING, "cannot copy src. %u<%u",
(unsigned)*src_len, (unsigned)len);
return -1;
}
memcpy(src, paddr, len);
*src_len = len;
}
found = 1;
}
}
#ifdef AF_LINK
else if((i == RTA_IFP) && (sa->sa_family == AF_LINK)) {
struct sockaddr_dl * sdl = (struct sockaddr_dl *)sa;
if(index)
*index = sdl->sdl_index;
}
#endif
/* at least 4 bytes per address are reserved,
* that is true with OpenBSD 4.3.
* The test is only useful when SA_SIZE() is not properly
* defined, as it should be always >= sizeof(long) */
if(SA_SIZE(sa) > 0)
p += SA_SIZE(sa);
else
p += sizeof(long);
}
}
}
return found ? 0 : -1;
}