5 files changed, 344 insertions, 38 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 81a41e7f..355fd103 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -397,6 +397,7 @@ auto_test(TCP)
 auto_test(bootstrap)
 auto_test(conference)
 auto_test(conference_double_invite)
+auto_test(conference_invite_merge)
 auto_test(conference_peer_nick)
 auto_test(conference_simple)
 auto_test(conference_two)
diff --git a/auto_tests/Makefile.inc b/auto_tests/Makefile.inc
index fcaeff5b..983c83d3 100644
--- a/auto_tests/Makefile.inc
+++ b/auto_tests/Makefile.inc
@@ -3,6 +3,7 @@ if BUILD_TESTS
 TESTS = \
         bootstrap_test \
         conference_double_invite_test \
+        conference_invite_merge_test \
         conference_peer_nick_test \
         conference_simple_test \
         conference_test \
@@ -73,6 +74,10 @@ conference_double_invite_test_SOURCES = ../auto_tests/conference_double_invite_t
 conference_double_invite_test_CFLAGS = $(AUTOTEST_CFLAGS)
 conference_double_invite_test_LDADD = $(AUTOTEST_LDADD)
 
+conference_invite_merge_test_SOURCES = ../auto_tests/conference_invite_merge_test.c
+conference_invite_merge_test_CFLAGS = $(AUTOTEST_CFLAGS)
+conference_invite_merge_test_LDADD = $(AUTOTEST_LDADD)
+
 conference_peer_nick_test_SOURCES = ../auto_tests/conference_peer_nick_test.c
 conference_peer_nick_test_CFLAGS = $(AUTOTEST_CFLAGS)
 conference_peer_nick_test_LDADD = $(AUTOTEST_LDADD)
diff --git a/auto_tests/conference_double_invite_test.c b/auto_tests/conference_double_invite_test.c
index 17124f1c..c9e64e5b 100644
--- a/auto_tests/conference_double_invite_test.c
+++ b/auto_tests/conference_double_invite_test.c
@@ -28,6 +28,8 @@ static void handle_conference_invite(
             state->index, friend_number, type, (unsigned)length);
     fprintf(stderr, "tox%u joining conference\n", state->index);
 
+    ck_assert_msg(!state->joined, "invitation callback generated for already joined conference");
+
     if (friend_number != -1) {
         Tox_Err_Conference_Join err;
         state->conference = tox_conference_join(tox, friend_number, cookie, length, &err);
@@ -71,7 +73,7 @@ static void conference_double_invite_test(Tox **toxes, State *state)
 
     fprintf(stderr, "Invitations accepted\n");
 
-    // Invite one more time, resulting in friend -1 inviting tox1 (toxes[1]).
+    fprintf(stderr, "Sending second invitation; should be ignored\n");
     tox_conference_invite(toxes[0], 0, state[0].conference, nullptr);
 
     iterate_all_wait(2, toxes, state, ITERATION_INTERVAL);
diff --git a/auto_tests/conference_invite_merge_test.c b/auto_tests/conference_invite_merge_test.c
new file mode 100644
index 00000000..e7ec499c
--- /dev/null
+++ b/auto_tests/conference_invite_merge_test.c
@@ -0,0 +1,244 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+typedef struct State {
+    uint32_t index;
+    uint64_t clock;
+
+    size_t save_size;
+    uint8_t *save_state;
+    bool alive;
+
+    bool connected;
+    uint32_t conference;
+} State;
+
+#define NUM_INVITE_MERGE_TOX 5
+
+#include "run_auto_test.h"
+
+static void handle_conference_invite(
+    Tox *tox, uint32_t friend_number, Tox_Conference_Type type,
+    const uint8_t *cookie, size_t length, void *user_data)
+{
+    State *state = (State *)user_data;
+
+    if (friend_number != -1) {
+        Tox_Err_Conference_Join err;
+        state->conference = tox_conference_join(tox, friend_number, cookie, length, &err);
+        ck_assert_msg(err == TOX_ERR_CONFERENCE_JOIN_OK,
+                      "attempting to join the conference returned with an error: %d", err);
+        fprintf(stderr, "#%u accepted invite to conference %u\n", state->index, state->conference);
+    }
+}
+
+static void handle_conference_connected(
+    Tox *tox, uint32_t conference_number, void *user_data)
+{
+    State *state = (State *)user_data;
+    fprintf(stderr, "#%u connected to conference %u\n", state->index, state->conference);
+    state->connected = true;
+}
+
+static void iterate_alive(Tox **toxes, State *state)
+{
+    for (uint32_t i = 0; i < NUM_INVITE_MERGE_TOX; i++) {
+        if (!state[i].alive) {
+            continue;
+        }
+
+        tox_iterate(toxes[i], &state[i]);
+        state[i].clock += ITERATION_INTERVAL;
+    }
+
+    c_sleep(20);
+}
+
+static void save(Tox **toxes, State *state, uint32_t n)
+{
+    fprintf(stderr, "Saving #%u\n", state[n].index);
+
+    if (state[n].save_state != nullptr) {
+        free(state[n].save_state);
+    }
+
+    state[n].save_size = tox_get_savedata_size(toxes[n]);
+    state[n].save_state = (uint8_t *)malloc(state[n].save_size);
+    ck_assert_msg(state[n].save_state != nullptr, "malloc failed");
+    tox_get_savedata(toxes[n], state[n].save_state);
+}
+
+static void kill(Tox **toxes, State *state, uint32_t n)
+{
+    fprintf(stderr, "Killing #%u\n", state[n].index);
+    state[n].alive = false;
+    tox_kill(toxes[n]);
+}
+
+static void reload(Tox **toxes, State *state, uint32_t n)
+{
+    if (state[n].alive) {
+        state[n].alive = false;
+        tox_kill(toxes[n]);
+    }
+
+    fprintf(stderr, "Reloading #%u\n", state[n].index);
+    ck_assert(state[n].save_state != nullptr);
+
+    struct Tox_Options *const options = tox_options_new(nullptr);
+    tox_options_set_savedata_type(options, TOX_SAVEDATA_TYPE_TOX_SAVE);
+    tox_options_set_savedata_data(options, state[n].save_state, state[n].save_size);
+    toxes[n] = tox_new_log(options, nullptr, &state[n].index);
+    tox_options_free(options);
+
+    set_mono_time_callback(toxes[n], &state[n]);
+    state[n].alive = true;
+}
+
+static void wait_connected(Tox **toxes, State *state, uint32_t n, uint32_t friendnumber)
+{
+    do {
+        iterate_alive(toxes, state);
+    } while (tox_friend_get_connection_status(toxes[n], friendnumber, nullptr) == TOX_CONNECTION_NONE);
+}
+
+static void do_invite(Tox **toxes, State *state, uint32_t inviter, uint32_t invitee, uint32_t friendnum)
+{
+    fprintf(stderr, "#%u inviting #%u\n", state[inviter].index, state[invitee].index);
+
+    Tox_Err_Conference_Invite err;
+    tox_conference_invite(toxes[inviter], friendnum, state[inviter].conference, &err);
+    ck_assert_msg(err == TOX_ERR_CONFERENCE_INVITE_OK,
+                  "#%u attempting to invite #%u (friendnumber %u) returned with an error: %d", state[inviter].index, state[invitee].index,
+                  friendnum, err);
+
+    do {
+        iterate_alive(toxes, state);
+    } while (!state[invitee].connected);
+}
+
+static bool group_complete(Tox **toxes, State *state)
+{
+    int c = -1, size = 0;
+
+    for (int i = 0; i < NUM_INVITE_MERGE_TOX; i++) {
+        if (!state[i].alive) {
+            continue;
+        }
+
+        const int ct = tox_conference_peer_count(toxes[i], state[i].conference, nullptr);
+
+        if (c == -1) {
+            c = ct;
+        } else if (c != ct) {
+            return false;
+        }
+
+        ++size;
+    }
+
+    return (c == size);
+}
+
+static void wait_group_complete(Tox **toxes, State *state)
+{
+    do {
+        iterate_alive(toxes, state);
+    } while (!group_complete(toxes, state));
+}
+
+static void conference_invite_merge_test(Tox **toxes, State *state)
+{
+    // Test that an explicit invite between peers in different connected
+    // components will cause a split group to merge
+
+    for (int i = 0; i < NUM_INVITE_MERGE_TOX; i++) {
+        tox_callback_conference_invite(toxes[i], handle_conference_invite);
+        tox_callback_conference_connected(toxes[i], &handle_conference_connected);
+        state[i].alive = true;
+        state[i].save_state = nullptr;
+    }
+
+    {
+        // Create new conference, tox 2 is the founder.
+        Tox_Err_Conference_New err;
+        state[2].conference = tox_conference_new(toxes[2], &err);
+        state[2].connected = true;
+        ck_assert_msg(err == TOX_ERR_CONFERENCE_NEW_OK,
+                      "attempting to create a new conference returned with an error: %d", err);
+        fprintf(stderr, "Created conference: index=%u\n", state[2].conference);
+    }
+
+    save(toxes, state, 2);
+
+    do_invite(toxes, state, 2, 1, 0);
+    do_invite(toxes, state, 1, 0, 0);
+
+    save(toxes, state, 1);
+    kill(toxes, state, 1);
+
+    do {
+        iterate_alive(toxes, state);
+    } while (tox_conference_peer_count(toxes[2], state[2].conference, nullptr) != 1);
+
+    do_invite(toxes, state, 2, 3, 1);
+    do_invite(toxes, state, 3, 4, 1);
+
+    kill(toxes, state, 2);
+
+    reload(toxes, state, 1);
+
+    uint8_t public_key[TOX_PUBLIC_KEY_SIZE];
+    tox_self_get_public_key(toxes[1], public_key);
+    tox_friend_add_norequest(toxes[3], public_key, nullptr);
+    tox_self_get_public_key(toxes[3], public_key);
+    tox_friend_add_norequest(toxes[1], public_key, nullptr);
+    wait_connected(toxes, state, 1, 2);
+
+    do_invite(toxes, state, 1, 3, 2);
+
+    fprintf(stderr, "Waiting for group to merge\n");
+
+    wait_group_complete(toxes, state);
+
+    fprintf(stderr, "Group merged\n");
+
+    reload(toxes, state, 2);
+    wait_connected(toxes, state, 2, 0);
+    do_invite(toxes, state, 2, 1, 0);
+
+    fprintf(stderr, "Waiting for #2 to rejoin\n");
+
+    wait_group_complete(toxes, state);
+
+    kill(toxes, state, 2);
+    wait_group_complete(toxes, state);
+    reload(toxes, state, 2);
+    wait_connected(toxes, state, 2, 0);
+    wait_connected(toxes, state, 1, 1);
+
+    do_invite(toxes, state, 1, 2, 1);
+
+    fprintf(stderr, "Waiting for #2 to rejoin\n");
+
+    wait_group_complete(toxes, state);
+
+    for (int i = 0; i < NUM_INVITE_MERGE_TOX; i++) {
+        if (state[i].save_state != nullptr) {
+            free(state[i].save_state);
+        }
+    }
+}
+
+int main(void)
+{
+    setvbuf(stdout, nullptr, _IONBF, 0);
+
+    run_auto_test(NUM_INVITE_MERGE_TOX, conference_invite_merge_test, true);
+    return 0;
+}
diff --git a/toxcore/group.c b/toxcore/group.c
index 50f6f2fe..b4248fd8 100644
--- a/toxcore/group.c
+++ b/toxcore/group.c
@@ -39,11 +39,13 @@ typedef enum Group_Message_Id {
 
 typedef enum Invite_Id {
     INVITE_ID             = 0,
-    INVITE_RESPONSE_ID    = 1,
+    INVITE_ACCEPT_ID      = 1,
+    INVITE_MEMBER_ID      = 2,
 } Invite_Id;
 
 #define INVITE_PACKET_SIZE (1 + sizeof(uint16_t) + 1 + GROUP_ID_LENGTH)
-#define INVITE_RESPONSE_PACKET_SIZE (1 + sizeof(uint16_t) * 2 + 1 + GROUP_ID_LENGTH)
+#define INVITE_ACCEPT_PACKET_SIZE (1 + sizeof(uint16_t) * 2 + 1 + GROUP_ID_LENGTH)
+#define INVITE_MEMBER_PACKET_SIZE (1 + sizeof(uint16_t) * 2 + 1 + GROUP_ID_LENGTH + sizeof(uint16_t))
 
 #define ONLINE_PACKET_DATA_SIZE (sizeof(uint16_t) + 1 + GROUP_ID_LENGTH)
 
@@ -1512,6 +1514,9 @@ static bool try_send_rejoin(Group_Chats *g_c, Group_c *g, const uint8_t *real_pk
 
 static unsigned int send_peer_query(Group_Chats *g_c, int friendcon_id, uint16_t group_num);
 
+static bool send_invite_response(Group_Chats *g_c, int groupnumber, uint32_t friendnumber, const uint8_t *data,
+                                 uint16_t length);
+
 /* Join a group (we need to have been invited first.)
  *
  * expected_type is the groupchat type we expect the chat we are joining to
@@ -1553,35 +1558,65 @@ int join_groupchat(Group_Chats *g_c, uint32_t friendnumber, uint8_t expected_typ
 
     Group_c *g = &g_c->chats[groupnumber];
 
-    const uint16_t group_num = net_htons(groupnumber);
     g->status = GROUPCHAT_STATUS_VALID;
     memcpy(g->real_pk, nc_get_self_public_key(g_c->m->net_crypto), CRYPTO_PUBLIC_KEY_SIZE);
 
-    uint8_t response[INVITE_RESPONSE_PACKET_SIZE];
-    response[0] = INVITE_RESPONSE_ID;
-    memcpy(response + 1, &group_num, sizeof(uint16_t));
-    memcpy(response + 1 + sizeof(uint16_t), data, sizeof(uint16_t) + 1 + GROUP_ID_LENGTH);
+    if (!send_invite_response(g_c, groupnumber, friendnumber, data, length)) {
+        g->status = GROUPCHAT_STATUS_NONE;
+        return -6;
+    }
+
+    return groupnumber;
+}
+
+static bool send_invite_response(Group_Chats *g_c, int groupnumber, uint32_t friendnumber, const uint8_t *data,
+                                 uint16_t length)
+{
+    Group_c *g = get_group_c(g_c, groupnumber);
+
+    const bool member = (g->status == GROUPCHAT_STATUS_CONNECTED);
+
+    VLA(uint8_t, response, member ? INVITE_MEMBER_PACKET_SIZE : INVITE_ACCEPT_PACKET_SIZE);
+    response[0] = member ? INVITE_MEMBER_ID : INVITE_ACCEPT_ID;
+    net_pack_u16(response + 1, groupnumber);
+    memcpy(response + 1 + sizeof(uint16_t), data, length);
+
+    if (member) {
+        net_pack_u16(response + 1 + sizeof(uint16_t) + length, g->peer_number);
+    }
+
+    if (!send_conference_invite_packet(g_c->m, friendnumber, response, SIZEOF_VLA(response))) {
+        return false;
+    }
 
-    if (send_conference_invite_packet(g_c->m, friendnumber, response, sizeof(response))) {
-        uint16_t other_groupnum;
-        memcpy(&other_groupnum, data, sizeof(other_groupnum));
-        other_groupnum = net_ntohs(other_groupnum);
+    if (!member) {
         g->type = data[sizeof(uint16_t)];
         memcpy(g->id, data + sizeof(uint16_t) + 1, GROUP_ID_LENGTH);
-        const int connection_index = add_conn_to_groupchat(g_c, friendcon_id, g,
-                                     GROUPCHAT_CONNECTION_REASON_INTRODUCER, 1);
+    }
 
-        if (connection_index != -1) {
-            g->connections[connection_index].group_number = other_groupnum;
-            g->connections[connection_index].type = GROUPCHAT_CONNECTION_ONLINE;
-        }
+    uint16_t other_groupnum;
+    net_unpack_u16(data, &other_groupnum);
 
-        send_peer_query(g_c, friendcon_id, other_groupnum);
-        return groupnumber;
+    const int friendcon_id = getfriendcon_id(g_c->m, friendnumber);
+
+    if (friendcon_id == -1) {
+        return false;
+    }
+
+    const int connection_index = add_conn_to_groupchat(g_c, friendcon_id, g, GROUPCHAT_CONNECTION_REASON_INTRODUCER, 1);
+
+    if (member) {
+        add_conn_to_groupchat(g_c, friendcon_id, g, GROUPCHAT_CONNECTION_REASON_INTRODUCING, 0);
     }
 
-    g->status = GROUPCHAT_STATUS_NONE;
-    return -6;
+    if (connection_index != -1) {
+        g->connections[connection_index].group_number = other_groupnum;
+        g->connections[connection_index].type = GROUPCHAT_CONNECTION_ONLINE;
+    }
+
+    send_peer_query(g_c, friendcon_id, other_groupnum);
+
+    return true;
 }
 
 /* Set handlers for custom lossy packets. */
@@ -1911,19 +1946,28 @@ static void handle_friend_invite_packet(Messenger *m, uint32_t friendnumber, con
                 }
 
                 return;
+            } else {
+                Group_c *g = get_group_c(g_c, groupnumber);
+
+                if (g && g->status == GROUPCHAT_STATUS_CONNECTED) {
+                    send_invite_response(g_c, groupnumber, friendnumber, invite_data, invite_length);
+                }
             }
 
             break;
         }
 
-        case INVITE_RESPONSE_ID: {
-            if (length != INVITE_RESPONSE_PACKET_SIZE) {
+        case INVITE_ACCEPT_ID:
+        case INVITE_MEMBER_ID: {
+            const bool member = (data[0] == INVITE_MEMBER_ID);
+
+            if (length != (member ? INVITE_MEMBER_PACKET_SIZE : INVITE_ACCEPT_PACKET_SIZE)) {
                 return;
             }
 
             uint16_t other_groupnum, groupnum;
-            memcpy(&groupnum, data + 1 + sizeof(uint16_t), sizeof(uint16_t));
-            groupnum = net_ntohs(groupnum);
+            net_unpack_u16(data + 1, &other_groupnum);
+            net_unpack_u16(data + 1 + sizeof(uint16_t), &groupnum);
 
             Group_c *g = get_group_c(g_c, groupnum);
 
@@ -1939,24 +1983,28 @@ static void handle_friend_invite_packet(Messenger *m, uint32_t friendnumber, con
                 return;
             }
 
-            /* TODO(irungentoo): what if two people enter the group at the same time and
-               are given the same peer_number by different nodes? */
-            uint16_t peer_number = random_u16();
+            uint16_t peer_number;
 
-            unsigned int tries = 0;
-
-            while (get_peer_index(g, peer_number) != -1 || get_frozen_index(g, peer_number) != -1) {
+            if (member) {
+                net_unpack_u16(data + 1 + sizeof(uint16_t) * 2 + 1 + GROUP_ID_LENGTH, &peer_number);
+            } else {
+                /* TODO(irungentoo): what if two people enter the group at the
+                 * same time and are given the same peer_number by different
+                 * nodes? */
                 peer_number = random_u16();
-                ++tries;
 
-                if (tries > 32) {
-                    return;
+                unsigned int tries = 0;
+
+                while (get_peer_index(g, peer_number) != -1 || get_frozen_index(g, peer_number) != -1) {
+                    peer_number = random_u16();
+                    ++tries;
+
+                    if (tries > 32) {
+                        return;
+                    }
                 }
             }
 
-            memcpy(&other_groupnum, data + 1, sizeof(uint16_t));
-            other_groupnum = net_ntohs(other_groupnum);
-
             const int friendcon_id = getfriendcon_id(m, friendnumber);
 
             if (friendcon_id == -1) {
@@ -1971,12 +2019,18 @@ static void handle_friend_invite_packet(Messenger *m, uint32_t friendnumber, con
             const int connection_index = add_conn_to_groupchat(g_c, friendcon_id, g,
                                          GROUPCHAT_CONNECTION_REASON_INTRODUCING, 1);
 
+            if (member) {
+                add_conn_to_groupchat(g_c, friendcon_id, g, GROUPCHAT_CONNECTION_REASON_INTRODUCER, 0);
+                send_peer_query(g_c, friendcon_id, other_groupnum);
+            }
+
             if (connection_index != -1) {
                 g->connections[connection_index].group_number = other_groupnum;
                 g->connections[connection_index].type = GROUPCHAT_CONNECTION_ONLINE;
             }
 
             group_new_peer_send(g_c, groupnum, peer_number, real_pk, temp_pk);
+
             break;
         }