From c874dc6d6b892a7697c0c83a070a5b0a564be55f Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Wed, 5 Aug 2009 14:47:16 -0700 Subject: [PATCH] secchan: Fix behavior when a network device is renamed. update_port() deals with the case where we have been notified that a network device with a given name, that is part of the datapath, has changed in some way. In particular it breaks the problem space up into ports that have been added, deleted, or modified. But the code here deals badly with the case where the only change is that the network device associated with a port has been renamed (which is reported to it with 'devname' as the network device's new named): it looks up devname in the ofproto's index by name and doesn't find it, then it looks up the port number assigned to the netdev in the ofproto's index by datapath index and sees that there already is one. This makes it think that it's a new port, but with a port number that conflicts with an existing port (under the old name for the port), which makes it discard the notification and keep the old netdev name, and so afterward nothing on the netdev will work since it still has the old netdev name. This rewrite fixes the problem and simplifies the code. --- secchan/ofproto.c | 92 ++++++++++++++++++++++++++++------------------- 1 file changed, 55 insertions(+), 37 deletions(-) diff --git a/secchan/ofproto.c b/secchan/ofproto.c index 9f3a84963..efa5c9b9e 100644 --- a/secchan/ofproto.c +++ b/secchan/ofproto.c @@ -1213,53 +1213,71 @@ static void update_port(struct ofproto *p, const char *devname) { struct odp_port odp_port; - struct ofport *ofport; + struct ofport *old_ofport; + struct ofport *new_ofport; int error; COVERAGE_INC(ofproto_update_port); - ofport = shash_find_data(&p->port_by_name, devname); + + /* Query the datapath for port information. */ error = dpif_port_query_by_name(&p->dpif, devname, &odp_port); - if (!error) { - if (!ofport) { - /* New port. */ - if (!ofport_conflicts(p, &odp_port)) { - ofport = make_ofport(&odp_port); - if (ofport) { - ofport_install(p, ofport); - send_port_status(p, ofport, OFPPR_ADD); - } - } - } else { - /* Modified port. */ - struct ofport *new_ofport = make_ofport(&odp_port); - if (!new_ofport) { - return; - } - new_ofport->opp.config &= OFPPC_PORT_DOWN; - new_ofport->opp.config |= ofport->opp.config & ~OFPPC_PORT_DOWN; - if (ofport_equal(ofport, new_ofport)) { - /* False alarm--no change. */ - ofport_free(new_ofport); - } else { - ofport_remove(p, ofport); - ofport_install(p, new_ofport); - ofport_free(ofport); - send_port_status(p, new_ofport, OFPPR_MODIFY); - } - } - } else if (error == ENOENT || error == ENODEV) { - /* Deleted port. */ - if (ofport) { - send_port_status(p, ofport, OFPPR_DELETE); - ofport_remove(p, ofport); - ofport_free(ofport); + /* Find the old ofport. */ + old_ofport = shash_find_data(&p->port_by_name, devname); + if (!error) { + if (!old_ofport) { + /* There's no port named 'devname' but there might be a port with + * the same port number. This could happen if a port is deleted + * and then a new one added in its place very quickly, or if a port + * is renamed. In the former case we want to send an OFPPR_DELETE + * and an OFPPR_ADD, and in the latter case we want to send a + * single OFPPR_MODIFY. We can distinguish the cases by comparing + * the old port's ifindex against the new port, or perhaps less + * reliably but more portably by comparing the old port's MAC + * against the new port's MAC. However, this code isn't that smart + * and always sends an OFPPR_MODIFY (XXX). */ + old_ofport = port_array_get(&p->ports, odp_port.port); } - } else { + } else if (error != ENOENT && error != ENODEV) { VLOG_WARN_RL(&rl, "dpif_port_query_by_name returned unexpected error " "%s", strerror(error)); return; } + + /* Create a new ofport. */ + new_ofport = !error ? make_ofport(&odp_port) : NULL; + + /* Eliminate a few pathological cases. */ + if (!old_ofport && !new_ofport) { + return; + } else if (old_ofport && new_ofport) { + /* Most of the 'config' bits are OpenFlow soft state, but + * OFPPC_PORT_DOWN is maintained the kernel. So transfer the OpenFlow + * bits from old_ofport. (make_ofport() only sets OFPPC_PORT_DOWN and + * leaves the other bits 0.) */ + new_ofport->opp.config |= old_ofport->opp.config & ~OFPPC_PORT_DOWN; + + if (ofport_equal(old_ofport, new_ofport)) { + /* False alarm--no change. */ + ofport_free(new_ofport); + return; + } + } + + /* Now deal with the normal cases. */ + if (old_ofport) { + ofport_remove(p, old_ofport); + } + if (new_ofport) { + ofport_install(p, new_ofport); + } + send_port_status(p, new_ofport ? new_ofport : old_ofport, + (!old_ofport ? OFPPR_ADD + : !new_ofport ? OFPPR_DELETE + : OFPPR_MODIFY)); + ofport_free(old_ofport); + + /* Update port groups. */ refresh_port_groups(p); } -- 2.20.1