diff options
| -rw-r--r-- | net/tipc/discover.c | 72 |
1 files changed, 58 insertions, 14 deletions
diff --git a/net/tipc/discover.c b/net/tipc/discover.c index 7ae1b4c33ae..f5f9bf7a043 100644 --- a/net/tipc/discover.c +++ b/net/tipc/discover.c @@ -122,7 +122,7 @@ void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) { struct tipc_node *n_ptr; struct tipc_link *link; - struct tipc_media_addr media_addr, *addr; + struct tipc_media_addr media_addr; struct sk_buff *rbuf; struct tipc_msg *msg = buf_msg(buf); u32 dest = msg_dest_domain(msg); @@ -130,13 +130,14 @@ void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) u32 net_id = msg_bc_netid(msg); u32 type = msg_type(msg); u32 signature = msg_node_sig(msg); + int addr_mismatch; int link_fully_up; media_addr.broadcast = 1; b_ptr->media->msg2addr(&media_addr, msg_media_addr(msg)); buf_discard(buf); - /* Validate discovery message from requesting node */ + /* Ensure message from node is valid and communication is permitted */ if (net_id != tipc_net_id) return; if (media_addr.broadcast) @@ -164,15 +165,50 @@ void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) } tipc_node_lock(n_ptr); + /* Prepare to validate requesting node's signature and media address */ link = n_ptr->links[b_ptr->identity]; + addr_mismatch = (link != NULL) && + memcmp(&link->media_addr, &media_addr, sizeof(media_addr)); - /* Create a link endpoint for this bearer, if necessary */ - if (!link) { - link = tipc_link_create(n_ptr, b_ptr, &media_addr); - if (!link) { + /* + * Ensure discovery message's signature is correct + * + * If signature is incorrect and there is no working link to the node, + * accept the new signature but invalidate all existing links to the + * node so they won't re-activate without a new discovery message. + * + * If signature is incorrect and the requested link to the node is + * working, accept the new signature. (This is an instance of delayed + * rediscovery, where a link endpoint was able to re-establish contact + * with its peer endpoint on a node that rebooted before receiving a + * discovery message from that node.) + * + * If signature is incorrect and there is a working link to the node + * that is not the requested link, reject the request (must be from + * a duplicate node). + */ + if (signature != n_ptr->signature) { + if (n_ptr->working_links == 0) { + struct tipc_link *curr_link; + int i; + + for (i = 0; i < MAX_BEARERS; i++) { + curr_link = n_ptr->links[i]; + if (curr_link) { + memset(&curr_link->media_addr, 0, + sizeof(media_addr)); + tipc_link_reset(curr_link); + } + } + addr_mismatch = (link != NULL); + } else if (tipc_link_is_up(link) && !addr_mismatch) { + /* delayed rediscovery */ + } else { + disc_dupl_alert(b_ptr, orig, &media_addr); tipc_node_unlock(n_ptr); return; } + n_ptr->signature = signature; } /* @@ -185,21 +221,29 @@ void tipc_disc_recv_msg(struct sk_buff *buf, struct tipc_bearer *b_ptr) * the new media address and reset the link to ensure it starts up * cleanly. */ - addr = &link->media_addr; - if (memcmp(addr, &media_addr, sizeof(*addr))) { - if (tipc_link_is_up(link) || (!link->started)) { + + if (addr_mismatch) { + if (tipc_link_is_up(link)) { disc_dupl_alert(b_ptr, orig, &media_addr); tipc_node_unlock(n_ptr); return; + } else { + memcpy(&link->media_addr, &media_addr, + sizeof(media_addr)); + tipc_link_reset(link); + } + } + + /* Create a link endpoint for this bearer, if necessary */ + if (!link) { + link = tipc_link_create(n_ptr, b_ptr, &media_addr); + if (!link) { + tipc_node_unlock(n_ptr); + return; } - warn("Resetting link <%s>, peer interface address changed\n", - link->name); - memcpy(addr, &media_addr, sizeof(*addr)); - tipc_link_reset(link); } /* Accept discovery message & send response, if necessary */ - n_ptr->signature = signature; link_fully_up = link_working_working(link); if ((type == DSC_REQ_MSG) && !link_fully_up && !b_ptr->blocked) { |