implement via-branch handling

(cherry picked from commit 77da616dd2)

Conflicts:
	daemon/str.h

Change-Id: Ie7f8a3cf2504322a511855eca8a68a43f7deb8f8

daemon/call.c

@@ -2427,10 +2427,11 @@ void call_destroy(struct call *c) {
 		}
 
 		ilog(LOG_INFO, "--- Tag '"STR_FORMAT"', created "
-				"%u:%02u ago, in dialogue with '"STR_FORMAT"'",
+				"%u:%02u ago for branch '"STR_FORMAT"', in dialogue with '"STR_FORMAT"'",
 				STR_FMT(&ml->tag),
 				(unsigned int) (poller_now - ml->created) / 60,
 				(unsigned int) (poller_now - ml->created) % 60,
+				STR_FMT(&ml->viabranch),
 				ml->active_dialogue ? ml->active_dialogue->tag.len : 6,
 				ml->active_dialogue ? ml->active_dialogue->tag.s : "(none)");
 
@@ -2684,6 +2685,7 @@ static void __call_free(void *p) {
 	}
 
 	g_hash_table_destroy(c->tags);
+	g_hash_table_destroy(c->viabranches);
 
 	while (c->streams) {
 		ps = c->streams->data;
@@ -2705,6 +2707,7 @@ static struct call *call_create(const str *callid, struct callmaster *m) {
 	call_buffer_init(&c->buffer);
 	rwlock_init(&c->master_lock);
 	c->tags = g_hash_table_new(str_hash, str_equal);
+	c->viabranches = g_hash_table_new(str_hash, str_equal);
 	call_str_cpy(c, &c->callid, callid);
 	c->created = poller_now;
 	c->dtls_cert = dtls_cert();
@@ -2795,6 +2798,18 @@ void __monologue_tag(struct call_monologue *ml, const str *tag) {
 	call_str_cpy(call, &ml->tag, tag);
 	g_hash_table_insert(call->tags, &ml->tag, ml);
 }
+static void __monologue_viabranch(struct call_monologue *ml, const str *viabranch) {
+	struct call *call = ml->call;
+
+	if (!viabranch)
+		return;
+
+	__C_DBG("tagging monologue with viabranch '"STR_FORMAT"'", STR_FMT(viabranch));
+	if (ml->viabranch.s)
+		g_hash_table_remove(call->viabranches, &ml->viabranch);
+	call_str_cpy(call, &ml->viabranch, viabranch);
+	g_hash_table_insert(call->viabranches, &ml->viabranch, ml);
+}
 
 static void __stream_unkernelize(struct packet_stream *ps) {
 	unkernelize(ps);
@@ -2857,8 +2872,8 @@ static void __monologue_destroy(struct call_monologue *monologue) {
 }
 
 /* must be called with call->master_lock held in W */
-static struct call_monologue *call_get_monologue(struct call *call, const str *fromtag) {
-	struct call_monologue *ret;
+static struct call_monologue *call_get_monologue(struct call *call, const str *fromtag, const str *viabranch) {
+	struct call_monologue *ret, *os;
 
 	__C_DBG("getting monologue for tag '"STR_FORMAT"' in call '"STR_FORMAT"'",
 			STR_FMT(fromtag), STR_FMT(&call->callid));
@@ -2867,74 +2882,109 @@ static struct call_monologue *call_get_monologue(struct call *call, const str *f
 		__C_DBG("found existing monologue");
 		__monologue_unkernelize(ret);
 		__monologue_unkernelize(ret->active_dialogue);
-		return ret;
+
+		if (!viabranch)
+			return ret;
+
+		/* check the viabranch. if it's not known, then this is a branched offer and we need
+		 * to create a new "other side" for this branch. */
+		if (!ret->active_dialogue->viabranch.s) {
+			/* previous "other side" hasn't been tagged with the via-branch, so we'll just
+			 * use this one and tag it */
+			__monologue_viabranch(ret->active_dialogue, viabranch);
+			return ret;
+		}
+		if (!str_cmp_str(&ret->active_dialogue->viabranch, viabranch))
+			return ret; /* dialogue still intact */
+		os = g_hash_table_lookup(call->viabranches, viabranch);
+		if (os) {
+			/* previously seen branch. use it */
+			__monologue_unkernelize(os);
+			os->active_dialogue = ret;
+			ret->active_dialogue = os;
+			return ret;
+		}
+		goto new_branch;
 	}
 
+	__C_DBG("creating new monologue");
 	ret = __monologue_create(call);
 	__monologue_tag(ret, fromtag);
 	/* we need both sides of the dialogue even in the initial offer, so create
 	 * another monologue without to-tag (to be filled in later) */
+new_branch:
+	__C_DBG("create new \"other side\" monologue for viabranch "STR_FORMAT, STR_FMT(viabranch));
 	ret->active_dialogue = __monologue_create(call);
+	__monologue_viabranch(ret->active_dialogue, viabranch);
 
 	return ret;
 }
 
 /* must be called with call->master_lock held in W */
-static struct call_monologue *call_get_dialogue(struct call *call, const str *fromtag, const str *totag) {
-	struct call_monologue *ft, *ret, *tt;
+static struct call_monologue *call_get_dialogue(struct call *call, const str *fromtag, const str *totag,
+		const str *viabranch)
+{
+	struct call_monologue *ft, *tt;
 
 	__C_DBG("getting dialogue for tags '"STR_FORMAT"'<>'"STR_FORMAT"' in call '"STR_FORMAT"'",
 			STR_FMT(fromtag), STR_FMT(totag), STR_FMT(&call->callid));
-	/* if the to-tag is known already, return that */
-	tt = g_hash_table_lookup(call->tags, totag);
-	if (tt) {
+
+	/* if the from-tag is known already, return that */
+	ft = g_hash_table_lookup(call->tags, fromtag);
+	if (ft) {
 		__C_DBG("found existing dialogue");
-		__monologue_unkernelize(tt);
-		__monologue_unkernelize(tt->active_dialogue);
 
 		/* make sure that the dialogue is actually intact */
-		if (!str_cmp_str(fromtag, &tt->active_dialogue->tag))
-			return tt;
+		/* fastpath for a common case */
+		if (!str_cmp_str(totag, &ft->active_dialogue->tag))
+			goto done;
+	}
+	else {
+		/* perhaps we can determine the monologue from the viabranch */
+		if (viabranch)
+			ft = g_hash_table_lookup(call->viabranches, viabranch);
 	}
 
-	/* otherwise, at least the from-tag has to be known. it's an error if it isn't */
-	ft = g_hash_table_lookup(call->tags, fromtag);
-	if (!ft)
+	/* the to-tag has to be known. it's an error if it isn't */
+	tt = g_hash_table_lookup(call->tags, totag);
+	if (!tt)
 		return NULL;
 
-	__monologue_unkernelize(ft);
-
-	/* check for a half-complete dialogue and fill in the missing half if possible */
-	ret = ft->active_dialogue;
-	__monologue_unkernelize(ret);
-
-	if (!ret->tag.s)
-		goto tag;
-
-	/* we may have seen both tags previously and they just need to be linked up */
-	if (tt) {
-		ret = tt;
-		goto link;
+	if (!ft) {
+		/* if we don't have a fromtag monologue yet, we can use a half-complete dialogue
+		 * from the totag if there is one. otherwise we have to create a new one. */
+		ft = tt->active_dialogue;
+		if (ft->tag.s)
+			ft = __monologue_create(call);
 	}
 
-	/* this is an additional dialogue created from a single from-tag */
-	ret = __monologue_create(call);
+	/* the fromtag monologue may be newly created, or half-complete from the totag, or
+	 * derived from the viabranch. */
+	if (!ft->tag.s)
+		__monologue_tag(ft, fromtag);
 
-tag:
-	__monologue_tag(ret, totag);
-link:
-	g_hash_table_insert(ret->other_tags, &ft->tag, ft);
-	g_hash_table_insert(ft->other_tags, &ret->tag, ret);
-	ret->active_dialogue = ft;
-	ft->active_dialogue = ret;
+	g_hash_table_insert(ft->other_tags, &tt->tag, tt);
+	g_hash_table_insert(tt->other_tags, &ft->tag, ft);
+	__monologue_unkernelize(ft->active_dialogue);
+	__monologue_unkernelize(tt->active_dialogue);
+	ft->active_dialogue = tt;
+	tt->active_dialogue = ft;
 
-	return ret;
+done:
+	__monologue_unkernelize(ft);
+	__monologue_unkernelize(ft->active_dialogue);
+	return ft;
 }
 
-struct call_monologue *call_get_mono_dialogue(struct call *call, const str *fromtag, const str *totag) {
-	if (!totag || !totag->s) /* offer, not answer */
-		return call_get_monologue(call, fromtag);
-	return call_get_dialogue(call, fromtag, totag);
+/* fromtag and totag strictly correspond to the directionality of the message, not to the actual
+ * SIP headers. IOW, the fromtag corresponds to the monologue sending this message, even if the
+ * tag is actually from the TO header of the SIP message (as it would be in a 200 OK) */
+struct call_monologue *call_get_mono_dialogue(struct call *call, const str *fromtag, const str *totag,
+		const str *viabranch)
+{
+	if (!totag || !totag->s) /* initial offer */
+		return call_get_monologue(call, fromtag, viabranch);
+	return call_get_dialogue(call, fromtag, totag, viabranch);
 }
 
 

daemon/call.h

@@ -324,6 +324,7 @@ struct call_monologue {
 	struct call		*call;		/* RO */
 
 	str			tag;
+	str			viabranch;
 	enum tag_type    tagtype;
 	time_t			created;	/* RO */
 	time_t			deleted;
@@ -348,7 +349,7 @@ struct call {
 	rwlock_t		master_lock;
 	GSList			*monologues;
 	GHashTable		*tags;	
-	//GHashTable		*branches;
+	GHashTable		*viabranches;
 	GSList			*streams;
 	GSList			*stream_fds;
 	struct dtls_cert	*dtls_cert; /* for outgoing */
@@ -443,7 +444,8 @@ struct packet_stream *__packet_stream_new(struct call *call);
 
 struct call *call_get_or_create(const str *callid, struct callmaster *m);
 struct call *call_get_opmode(const str *callid, struct callmaster *m, enum call_opmode opmode);
-struct call_monologue *call_get_mono_dialogue(struct call *call, const str *fromtag, const str *totag);
+struct call_monologue *call_get_mono_dialogue(struct call *call, const str *fromtag, const str *totag,
+		const str *viabranch);
 struct call *call_get(const str *callid, struct callmaster *m);
 int monologue_offer_answer(struct call_monologue *monologue, GQueue *streams, const struct sdp_ng_flags *flags);
 int call_delete_branch(struct callmaster *m, const str *callid, const str *branch,

daemon/call_interfaces.c

@@ -145,8 +145,9 @@ static str *call_update_lookup_udp(char **out, struct callmaster *m, enum call_o
 	str_init(&callid, out[RE_UDP_UL_CALLID]);
 	str_init(&viabranch, out[RE_UDP_UL_VIABRANCH]);
 	str_init(&fromtag, out[RE_UDP_UL_FROMTAG]);
+	str_init(&totag, out[RE_UDP_UL_TOTAG]);
 	if (opmode == OP_ANSWER)
-		str_init(&totag, out[RE_UDP_UL_TOTAG]);
+		str_swap(&fromtag, &totag);
 
 	c = call_get_opmode(&callid, m, opmode);
 	if (!c) {
@@ -159,11 +160,11 @@ static str *call_update_lookup_udp(char **out, struct callmaster *m, enum call_o
 		c->created_from = call_strdup(c, addr);
 	}
 
-	monologue = call_get_mono_dialogue(c, &fromtag, &totag);
+	monologue = call_get_mono_dialogue(c, &fromtag, &totag, NULL);
 	if (!monologue)
 		goto ml_fail;
 
-	if (!totag.s || totag.len==0) {
+	if (opmode == OP_OFFER) {
 		monologue->tagtype = FROM_TAG;
 	} else {
 		monologue->tagtype = TO_TAG;
@@ -305,15 +306,16 @@ static str *call_request_lookup_tcp(char **out, struct callmaster *m, enum call_
 		ilog(LOG_WARNING, "No from-tag in message");
 		goto out2;
 	}
+	str_init(&totag, g_hash_table_lookup(infohash, "totag"));
 	if (opmode == OP_ANSWER) {
-		str_init(&totag, g_hash_table_lookup(infohash, "totag"));
 		if (!totag.s) {
 			ilog(LOG_WARNING, "No to-tag in message");
 			goto out2;
 		}
+		str_swap(&fromtag, &totag);
 	}
 
-	monologue = call_get_mono_dialogue(c, &fromtag, &totag);
+	monologue = call_get_mono_dialogue(c, &fromtag, &totag, NULL);
 	if (!monologue) {
 		ilog(LOG_WARNING, "Invalid dialogue association");
 		goto out2;
@@ -594,7 +596,7 @@ static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *inpu
 static const char *call_offer_answer_ng(bencode_item_t *input, struct callmaster *m,
 		bencode_item_t *output, enum call_opmode opmode, const char* addr)
 {
-	str sdp, fromtag, totag = STR_NULL, callid;
+	str sdp, fromtag, totag = STR_NULL, callid, viabranch;
 	char *errstr;
 	GQueue parsed = G_QUEUE_INIT;
 	GQueue streams = G_QUEUE_INIT;
@@ -610,11 +612,13 @@ static const char *call_offer_answer_ng(bencode_item_t *input, struct callmaster
 		return "No call-id in message";
 	if (!bencode_dictionary_get_str(input, "from-tag", &fromtag))
 		return "No from-tag in message";
+	bencode_dictionary_get_str(input, "to-tag", &totag);
 	if (opmode == OP_ANSWER) {
-		if (!bencode_dictionary_get_str(input, "to-tag", &totag))
+		if (!totag.s)
 			return "No to-tag in message";
+		str_swap(&totag, &fromtag);
 	}
-	//bencode_dictionary_get_str(input, "via-branch", &viabranch);
+	bencode_dictionary_get_str(input, "via-branch", &viabranch);
 
 	if (sdp_parse(&sdp, &parsed))
 		return "Failed to parse SDP";
@@ -638,7 +642,7 @@ static const char *call_offer_answer_ng(bencode_item_t *input, struct callmaster
 	 * need to hold a ref until we're done sending the reply */
 	call_bencode_hold_ref(call, output);
 
-	monologue = call_get_mono_dialogue(call, &fromtag, &totag);
+	monologue = call_get_mono_dialogue(call, &fromtag, &totag, viabranch.s ? &viabranch : NULL);
 	errstr = "Invalid dialogue association";
 	if (!monologue) {
 		rwlock_unlock_w(&call->master_lock);
@@ -646,7 +650,7 @@ static const char *call_offer_answer_ng(bencode_item_t *input, struct callmaster
 		goto out;
 	}
 
-	if (!totag.s || totag.len==0) {
+	if (opmode == OP_OFFER) {
 		monologue->tagtype = FROM_TAG;
 	} else {
 		monologue->tagtype = TO_TAG;
@@ -849,6 +853,8 @@ static void ng_stats_monologue(bencode_item_t *dict, const struct call_monologue
 	sub = bencode_dictionary_add_dictionary(dict, ml->tag.s);
 
 	bencode_dictionary_add_str(sub, "tag", &ml->tag);
+	if (ml->viabranch.s)
+		bencode_dictionary_add_str(sub, "via-branch", &ml->viabranch);
 	bencode_dictionary_add_integer(sub, "created", ml->created);
 	if (ml->active_dialogue)
 		bencode_dictionary_add_str(sub, "in dialogue with", &ml->active_dialogue->tag);

daemon/str.h

@@ -56,6 +56,10 @@ INLINE str *str_chunk_insert(GStringChunk *c, const str *s);
 INLINE int str_shift(str *s, int len);
 /* binary compares str object with memory chunk of equal size */
 INLINE int str_memcmp(const str *s, void *m);
+/* locate a substring within a string, returns character index or -1 */
+INLINE int str_str(const str *s, const char *sub);
+/* swaps the contents of two str objects */
+INLINE void str_swap(str *a, str *b);
 
 /* asprintf() analogs */
 #define str_sprintf(fmt, a...) __str_sprintf(STR_MALLOC_PADDING fmt, a)
@@ -208,5 +212,28 @@ INLINE str *g_string_free_str(GString *gs) {
 INLINE int str_memcmp(const str *s, void *m) {
 	return memcmp(s->s, m, s->len);
 }
+INLINE int str_str(const str *s, const char *sub) {
+	int len = strlen(sub);
+	void *p, *e;
+
+	p = s->s;
+	e = p + (s->len - len);
+	while (p < e) {
+		p = memchr(p, sub[0], e - p);
+		if (!p)
+			return -1;
+		if (!memcmp(p, sub, len))
+			return p - (void *) s->s;
+		p++;
+	}
+
+	return -1;
+}
+INLINE void str_swap(str *a, str *b) {
+	str t;
+	t = *a;
+	*a = *b;
+	*b = t;
+}
 
 #endif

utils/ng-client

@@ -19,6 +19,7 @@ GetOptions(
 	'from-tag=s'			=> \$options{'from-tag'},
 	'to-tag=s'			=> \$options{'to-tag'},
 	'call-id=s'			=> \$options{'call-id'},
+	'via-branch=s'			=> \$options{'via-branch'},
 	'protocol=s'			=> \$options{'transport protocol'},
 	'trust-address'			=> \$options{'trust address'},
 	'sip-source-address'		=> \$options{'sip source address'},
@@ -48,7 +49,7 @@ my $cmd = shift(@ARGV) or die;
 
 my %packet = (command => $cmd);
 
-for my $x (split(',', 'from-tag,to-tag,call-id,transport protocol,media address,ICE,address family,TOS,DTLS')) {
+for my $x (split(',', 'from-tag,to-tag,call-id,transport protocol,media address,ICE,address family,TOS,DTLS,via-branch')) {
 	defined($options{$x}) and $packet{$x} = $options{$x};
 }
 for my $x (split(',', 'trust address,symmetric,asymmetric,force,strict source,media handover,sip source address')) {