int
dna_helper_enqueue(struct subscriber *source, mdp_port_t source_port, const char *did)
{
if (config.debug.dnahelper)
DEBUGF("DNAHELPER request did=%s sid=%s", did, alloca_tohex_sid_t(source->sid));
if (dna_helper_pid == 0)
return 0;
// Only try to restart a DNA helper process if the previous one is well and truly gone.
if (dna_helper_pid == -1 && dna_helper_stdin == -1 && dna_helper_stdout == -1 && dna_helper_stderr == -1) {
if (dna_helper_start() == -1) {
/* Something broke, bail out */
return WHY("DNAHELPER start failed");
}
}
/* Write request to dna helper.
Request takes form: SID-of-Requestor|DID|\n
By passing the requestor's SID to the helper, we don't need to maintain
any state, as all we have to do is wait for responses from the helper,
which will include the requestor's SID.
*/
if (dna_helper_stdin == -1)
return 0;
if (request_bufptr && request_bufptr != request_buffer) {
WARNF("DNAHELPER currently sending request %s -- dropping new request", request_buffer);
return 0;
}
if (awaiting_reply) {
WARN("DNAHELPER currently awaiting reply -- dropping new request");
return 0;
}
char buffer[sizeof request_buffer];
strbuf b = strbuf_local(request_bufptr == request_buffer ? buffer : request_buffer, sizeof buffer);
strbuf_tohex(b, SID_STRLEN, source->sid.binary);
strbuf_putc(b, '|');
strbuf_puts(b, did);
strbuf_putc(b, '|');
strbuf_putc(b, '\n');
if (strbuf_overrun(b)) {
WHYF("DNAHELPER request buffer overrun: %s -- request not sent", strbuf_str(b));
request_bufptr = request_bufend = NULL;
} else {
if (strbuf_str(b) != request_buffer) {
if (strcmp(strbuf_str(b), request_buffer) != 0)
WARNF("DNAHELPER overwriting unsent request %s", request_buffer);
strcpy(request_buffer, strbuf_str(b));
}
request_bufptr = request_buffer;
request_bufend = request_buffer + strbuf_len(b);
request_source = source;
request_port = source_port;
strncpy(request_did, did, sizeof request_did);
request_did[sizeof request_did - 1] = '\0';
}
if (dna_helper_started) {
sched_requests.poll.fd = dna_helper_stdin;
watch(&sched_requests);
}
return 1;
}
int overlay_mdp_dnalookup_reply(const sockaddr_mdp *dstaddr, const unsigned char *resolved_sid, const char *uri, const char *did, const char *name)
{
overlay_mdp_frame mdpreply;
bzero(&mdpreply, sizeof mdpreply);
mdpreply.packetTypeAndFlags = MDP_TX; // outgoing MDP message
memcpy(mdpreply.out.src.sid, resolved_sid, SID_SIZE);
mdpreply.out.src.port = MDP_PORT_DNALOOKUP;
bcopy(dstaddr, &mdpreply.out.dst, sizeof(sockaddr_mdp));
/* build reply as TOKEN|URI|DID|NAME|<NUL> */
strbuf b = strbuf_local((char *)mdpreply.out.payload, sizeof mdpreply.out.payload);
strbuf_tohex(b, resolved_sid, SID_SIZE);
strbuf_sprintf(b, "|%s|%s|%s|", uri, did, name);
if (strbuf_overrun(b))
return WHY("MDP payload overrun");
mdpreply.out.payload_length = strbuf_len(b) + 1;
/* deliver reply */
return overlay_mdp_dispatch(&mdpreply, 0 /* system generated */, NULL, 0);
}
int overlay_saw_mdp_frame(overlay_mdp_frame *mdp, time_ms_t now)
{
IN();
int i;
int match=-1;
switch(mdp->packetTypeAndFlags&MDP_TYPE_MASK) {
case MDP_TX:
/* Regular MDP frame addressed to us. Look for matching port binding,
and if available, push to client. Else do nothing, or if we feel nice
send back a connection refused type message? Silence is probably the
more prudent path.
*/
if (debug & DEBUG_MDPREQUESTS)
DEBUGF("Received packet with listener (MDP ports: src=%s*:%d, dst=%d)",
alloca_tohex(mdp->out.src.sid, 7),
mdp->out.src.port,mdp->out.dst.port);
// TODO pass in dest subscriber as an argument, we should know it by now
struct subscriber *destination = NULL;
if (!is_broadcast(mdp->out.dst.sid)){
destination = find_subscriber(mdp->out.dst.sid, SID_SIZE, 1);
}
for(i=0;i<MDP_MAX_BINDINGS;i++)
{
if (mdp_bindings[i].port!=mdp->out.dst.port)
continue;
if ((!destination) || mdp_bindings[i].subscriber == destination){
/* exact match, so stop searching */
match=i;
break;
}else if (!mdp_bindings[i].subscriber){
/* If we find an "ANY" binding, remember it. But we will prefer an exact match if we find one */
match=i;
}
}
if (match>-1) {
struct sockaddr_un addr;
bcopy(mdp_bindings[match].socket_name,addr.sun_path,mdp_bindings[match].name_len);
addr.sun_family=AF_UNIX;
errno=0;
int len=overlay_mdp_relevant_bytes(mdp);
int r=sendto(mdp_named.poll.fd,mdp,len,0,(struct sockaddr*)&addr,sizeof(addr));
if (r==overlay_mdp_relevant_bytes(mdp)) {
RETURN(0);
}
WHY("didn't send mdp packet");
if (errno==ENOENT) {
/* far-end of socket has died, so drop binding */
INFOF("Closing dead MDP client '%s'",mdp_bindings[match].socket_name);
overlay_mdp_releasebindings(&addr,mdp_bindings[match].name_len);
}
WHY_perror("sendto(e)");
RETURN(WHY("Failed to pass received MDP frame to client"));
} else {
/* No socket is bound, ignore the packet ... except for magic sockets */
switch(mdp->out.dst.port) {
case MDP_PORT_VOMP:
RETURN(vomp_mdp_received(mdp));
case MDP_PORT_KEYMAPREQUEST:
/* Either respond with the appropriate SAS, or record this one if it
verifies out okay. */
if (debug & DEBUG_MDPREQUESTS)
DEBUG("MDP_PORT_KEYMAPREQUEST");
RETURN(keyring_mapping_request(keyring,mdp));
case MDP_PORT_DNALOOKUP: /* attempt to resolve DID to SID */
{
int cn=0,in=0,kp=0;
char did[64+1];
int pll=mdp->out.payload_length;
if (pll>64) pll=64;
/* get did from the packet */
if (mdp->out.payload_length<1) {
RETURN(WHY("Empty DID in DNA resolution request")); }
bcopy(&mdp->out.payload[0],&did[0],pll);
did[pll]=0;
if (debug & DEBUG_MDPREQUESTS)
DEBUG("MDP_PORT_DNALOOKUP");
int results=0;
while(keyring_find_did(keyring,&cn,&in,&kp,did))
{
/* package DID and Name into reply (we include the DID because
it could be a wild-card DID search, but the SID is implied
in the source address of our reply). */
if (keyring->contexts[cn]->identities[in]->keypairs[kp]->private_key_len > DID_MAXSIZE)
/* skip excessively long DID records */
continue;
const unsigned char *packedSid = keyring->contexts[cn]->identities[in]->keypairs[0]->public_key;
const char *unpackedDid = (const char *) keyring->contexts[cn]->identities[in]->keypairs[kp]->private_key;
const char *name = (const char *)keyring->contexts[cn]->identities[in]->keypairs[kp]->public_key;
// URI is sid://SIDHEX/DID
strbuf b = strbuf_alloca(SID_STRLEN + DID_MAXSIZE + 10);
strbuf_puts(b, "sid://");
strbuf_tohex(b, packedSid, SID_SIZE);
strbuf_puts(b, "/local/");
strbuf_puts(b, unpackedDid);
overlay_mdp_dnalookup_reply(&mdp->out.src, packedSid, strbuf_str(b), unpackedDid, name);
kp++;
results++;
}
if (!results) {
/* No local results, so see if servald has been configured to use
a DNA-helper that can provide additional mappings. This provides
a generalised interface for resolving telephone numbers into URIs.
The first use will be for resolving DIDs to SIP addresses for
OpenBTS boxes run by the OTI/Commotion project.
The helper is run asynchronously, and the replies will be delivered
when results become available, so this function will return
immediately, so as not to cause blockages and delays in servald.
*/
dna_helper_enqueue(mdp, did, mdp->out.src.sid);
monitor_tell_formatted(MONITOR_DNAHELPER, "LOOKUP:%s:%d:%s\n", alloca_tohex_sid(mdp->out.src.sid), mdp->out.src.port, did);
}
RETURN(0);
}
break;
case MDP_PORT_ECHO: /* well known ECHO port for TCP/UDP and now MDP */
{
/* Echo is easy: we swap the sender and receiver addresses (and thus port
numbers) and send the frame back. */
/* Swap addresses */
overlay_mdp_swap_src_dst(mdp);
/* Prevent echo:echo connections and the resulting denial of service from triggering endless pongs. */
if (mdp->out.dst.port==MDP_PORT_ECHO) {
RETURN(WHY("echo loop averted"));
}
/* If the packet was sent to broadcast, then replace broadcast address
with our local address. For now just responds with first local address */
if (is_broadcast(mdp->out.src.sid))
{
if (my_subscriber)
bcopy(my_subscriber->sid,
mdp->out.src.sid,SID_SIZE);
else
/* No local addresses, so put all zeroes */
bzero(mdp->out.src.sid,SID_SIZE);
}
/* queue frame for delivery */
overlay_mdp_dispatch(mdp,0 /* system generated */,
NULL,0);
/* and switch addresses back around in case the caller was planning on
using MDP structure again (this happens if there is a loop-back reply
and the frame needs sending on, as happens with broadcasts. MDP ping
is a simple application where this occurs). */
overlay_mdp_swap_src_dst(mdp);
}
break;
default:
/* Unbound socket. We won't be sending ICMP style connection refused
messages, partly because they are a waste of bandwidth. */
RETURN(WHYF("Received packet for which no listening process exists (MDP ports: src=%d, dst=%d",
mdp->out.src.port,mdp->out.dst.port));
}
}
break;
default:
RETURN(WHYF("We should only see MDP_TX frames here (MDP message type = 0x%x)",
mdp->packetTypeAndFlags));
}
RETURN(0);
}
