static stream_t open_dst(stream_addr_t* addr, const caphead_t cp, const char* comment){
/* default to stdout */
if( !stream_addr_is_set(addr) ){
if ( isatty(STDOUT_FILENO) ){
fprintf(stderr, "%s: Cannot output to a terminal, either specify a file using `-o FILENAME' or\n"
" redirect output.\n", program_name);
return NULL;
}
/* stdout is not a terminal so user probably want to use redirection */
stream_addr_str(addr, "/dev/stdout", 0);
}
if ( !quiet ){
fprintf(stderr, "%s: Opening file stream: %s\n", program_name, stream_addr_ntoa(addr));
}
int ret;
stream_t st = NULL;
if ( (ret=stream_create(&st, addr, cp->nic, cp->mampid, comment)) != 0 ){
fprintf(stderr, "%s: stream_create failed with code %d: %s.\n", program_name, ret, caputils_error_string(ret));
return NULL;
}
return st;
}
void send_packet(struct destination* dst){
const size_t payload_size = dst->buffer.end - dst->buffer.begin;
const uint32_t seqnr = ntohl(dst->shead->sequencenr);
assert(payload_size > 0);
dst->shead->flags = htonl(dst->shead->flags);
dst->shead->nopkts = htonl(dst->sendcount);
/* see destination.h for buffer layout */
const u_char* data = dst->buffer.begin;
size_t frame_size = payload_size;
/* send header is prepended to data and must be included in size */
if ( dst->want_sendhead ){
data -= sizeof(struct sendhead);
frame_size += sizeof(struct sendhead);
}
assert(frame_size <= MPinfo->MTU && "send_packet(..) payload size is greater than MTU");
/* ethernet streams requires ethernet header to be prepended */
if ( dst->want_ethhead ){
data -= sizeof(struct ethhdr);
frame_size += sizeof(struct ethhdr);
}
int ret = stream_write(dst->stream, data, frame_size);
logmsg(verbose, SENDER, "Filter %d sending %zd bytes with %d packets\n", dst->filter->filter_id, frame_size, ntohl(dst->shead->nopkts));
if ( debug_flag ){
if ( ret == 0 ){
logmsg(verbose, SENDER, "\tcaputils-%s\n", caputils_version(NULL));
logmsg(verbose, SENDER, "\tdst: %s\n", stream_addr_ntoa(&dst->filter->dest));
logmsg(verbose, SENDER, "\tPacket (%zd bytes incl all headers):\n", frame_size);
if ( dst->want_ethhead ){
logmsg(verbose, SENDER, "\t\tEthernet (+%zd bytes)\n", sizeof(struct ethhdr));
}
if ( dst->want_sendhead ){
logmsg(verbose, SENDER, "\t\tSendheader [Seqnr=%04lx, nopkts=%04d] (+%zd bytes)\n", (unsigned long int)seqnr, ntohl(dst->shead->nopkts), sizeof(struct sendhead));
}
logmsg(verbose, SENDER, "\t\tPayload (+%zd bytes)\n", payload_size);
logmsg(verbose, SENDER, "\tsizeof(caphead): %zd bytes\n", sizeof(struct cap_header));
logmsg(verbose, SENDER, "\tMTU: %zd bytes\n", MPinfo->MTU);
} else {
logmsg(stderr, SENDER, "\tstream_write() returned %d: %s\n", ret, strerror(ret));
logmsg(verbose, SENDER, "\tPacket length = %zd bytes, Eth %zd, Send %zd, Cap %zd bytes\n", frame_size, sizeof(struct ethhdr), sizeof(struct sendhead), sizeof(struct cap_header));
}
}
//Update the sequence number and reset
dst->shead->sequencenr = htonl((seqnr+1) % 0xFFFF);
dst->shead->flags = 0;
dst->sendcount = 0;
/* update stats */
MPstats->written_count += dst->sendcount;
MPstats->sent_count++;
/* restore packet buffer */
dst->buffer.end = dst->buffer.begin;
}
