Commit 85cd01c1 authored by Jakub Adam's avatar Jakub Adam Committed by Philip Withnall

ms-ice: ensure distinct candidate priority for multihomed hosts

Offering multiple host candidates with equal priorities could lead to unpredictable candidate pair selection by our counterparty.

Fixes call disconnection by MS Lync client after 30 seconds while VPN (2nd IP) was active on libnice host.

Maniphest Tasks: T3324

Reviewers: pwithnall

Projects: #libnice

Reviewed By: pwithnall

Subscribers: pwithnall

Differential Revision:
parent 88ed4261
......@@ -52,6 +52,7 @@
#include "agent.h"
#include "component.h"
#include "interfaces.h"
G_DEFINE_BOXED_TYPE (NiceCandidate, nice_candidate, nice_candidate_copy,
......@@ -144,6 +145,43 @@ nice_candidate_ice_local_preference_full (guint direction_preference,
static guint8
nice_candidate_ip_local_preference (const NiceCandidate *candidate)
guint8 preference = 0;
gchar ip_string[INET6_ADDRSTRLEN];
GList/*<owned gchar*>*/ *ips = NULL;
GList/*<unowned gchar*>*/ *iter;
/* Ensure otherwise identical host candidates with only different IP addresses
* (multihomed host) get assigned different priorities. Position of the IP in
* the list obtained from nice_interfaces_get_local_ips() serves here as the
* distinguishing value of other_preference. Reflexive and relayed candidates
* are likewise differentiated by their base address.
* This is required by RFC 5245 Section
if (candidate->type == NICE_CANDIDATE_TYPE_HOST) {
nice_address_to_string (&candidate->addr, ip_string);
} else {
nice_address_to_string (&candidate->base_addr, ip_string);
ips = nice_interfaces_get_local_ips (TRUE);
for (iter = ips; iter; iter = g_list_next (iter)) {
if (g_strcmp0 (ip_string, iter->data) == 0) {
g_list_free_full (ips, g_free);
return preference;
static guint16
nice_candidate_ice_local_preference (const NiceCandidate *candidate)
......@@ -214,7 +252,7 @@ nice_candidate_ms_ice_local_preference (const NiceCandidate *candidate)
return nice_candidate_ms_ice_local_preference_full(transport_preference,
direction_preference, 0);
direction_preference, nice_candidate_ip_local_preference (candidate));
static guint8
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