serval-dna/mdp_net.c

75 lines
2.3 KiB
C

/*
Copyright (C) 2013 Serval Project Inc.
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.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "socket.h"
#include "conf.h"
#include "log.h"
ssize_t recvwithttl(int sock,unsigned char *buffer, size_t bufferlen,int *ttl, struct socket_address *recvaddr)
{
struct msghdr msg;
struct iovec iov[1];
struct cmsghdr cmsgcmsg[16];
iov[0].iov_base=buffer;
iov[0].iov_len=bufferlen;
bzero(&msg,sizeof(msg));
msg.msg_name = &recvaddr->store;
msg.msg_namelen = sizeof(recvaddr->store);
msg.msg_iov = &iov[0];
msg.msg_iovlen = 1;
msg.msg_control = cmsgcmsg;
msg.msg_controllen = sizeof cmsgcmsg;
msg.msg_flags = 0;
ssize_t len = recvmsg(sock,&msg,0);
if (len == -1 && errno != EAGAIN && errno != EWOULDBLOCK)
return WHYF_perror("recvmsg(%d,%p,0)", sock, &msg);
#if 0
if (config.debug.packetrx) {
DEBUGF("recvmsg returned %d (flags=%d, msg_controllen=%d)", (int) len, msg.msg_flags, (int)msg.msg_controllen);
dump("received data", buffer, len);
}
#endif
if (len > 0) {
struct cmsghdr *cmsg;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if ( cmsg->cmsg_level == IPPROTO_IP
&& ((cmsg->cmsg_type == IP_RECVTTL) || (cmsg->cmsg_type == IP_TTL))
&& cmsg->cmsg_len
) {
if (config.debug.packetrx)
DEBUGF(" TTL (%p) data location resolves to %p", ttl,CMSG_DATA(cmsg));
if (CMSG_DATA(cmsg)) {
*ttl = *(unsigned char *) CMSG_DATA(cmsg);
if (config.debug.packetrx)
DEBUGF(" TTL of packet is %d", *ttl);
}
} else {
if (config.debug.packetrx)
DEBUGF("I didn't expect to see level=%02x, type=%02x",
cmsg->cmsg_level,cmsg->cmsg_type);
}
}
}
recvaddr->addrlen = msg.msg_namelen;
return len;
}