mirror of
https://github.com/servalproject/serval-dna.git
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75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/*
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Copyright (C) 2013 Serval Project Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "socket.h"
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#include "conf.h"
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#include "log.h"
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ssize_t recvwithttl(int sock,unsigned char *buffer, size_t bufferlen,int *ttl, struct socket_address *recvaddr)
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{
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struct msghdr msg;
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struct iovec iov[1];
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struct cmsghdr cmsgcmsg[16];
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iov[0].iov_base=buffer;
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iov[0].iov_len=bufferlen;
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bzero(&msg,sizeof(msg));
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msg.msg_name = &recvaddr->store;
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msg.msg_namelen = recvaddr->addrlen;
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msg.msg_iov = &iov[0];
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msg.msg_iovlen = 1;
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msg.msg_control = cmsgcmsg;
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msg.msg_controllen = sizeof cmsgcmsg;
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msg.msg_flags = 0;
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ssize_t len = recvmsg(sock,&msg,0);
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if (len == -1 && errno != EAGAIN && errno != EWOULDBLOCK)
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return WHYF_perror("recvmsg(%d,%p,0)", sock, &msg);
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#if 0
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if (config.debug.packetrx) {
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DEBUGF("recvmsg returned %d (flags=%d, msg_controllen=%d)", (int) len, msg.msg_flags, (int)msg.msg_controllen);
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dump("received data", buffer, len);
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}
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#endif
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if (len > 0) {
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struct cmsghdr *cmsg;
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for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
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if ( cmsg->cmsg_level == IPPROTO_IP
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&& ((cmsg->cmsg_type == IP_RECVTTL) || (cmsg->cmsg_type == IP_TTL))
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&& cmsg->cmsg_len
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) {
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if (config.debug.packetrx)
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DEBUGF(" TTL (%p) data location resolves to %p", ttl,CMSG_DATA(cmsg));
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if (CMSG_DATA(cmsg)) {
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*ttl = *(unsigned char *) CMSG_DATA(cmsg);
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if (config.debug.packetrx)
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DEBUGF(" TTL of packet is %d", *ttl);
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}
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} else {
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if (config.debug.packetrx)
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DEBUGF("I didn't expect to see level=%02x, type=%02x",
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cmsg->cmsg_level,cmsg->cmsg_type);
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}
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}
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}
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recvaddr->addrlen = msg.msg_namelen;
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return len;
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}
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