diff options
Diffstat (limited to 'sys/netinet/tcp_subr.c')
| -rw-r--r-- | sys/netinet/tcp_subr.c | 65 |
1 files changed, 63 insertions, 2 deletions
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c index e6e7ca4..eebc023 100644 --- a/sys/netinet/tcp_subr.c +++ b/sys/netinet/tcp_subr.c @@ -278,8 +278,6 @@ tcp_init(void) { int hashsize; - cc_init(); - hashsize = TCBHASHSIZE; TUNABLE_INT_FETCH("net.inet.tcp.tcbhashsize", &hashsize); if (!powerof2(hashsize)) { @@ -710,6 +708,69 @@ tcp_newtcpcb(struct inpcb *inp) } /* + * Switch the congestion control algorithm back to NewReno for any active + * control blocks using an algorithm which is about to go away. + * This ensures the CC framework can allow the unload to proceed without leaving + * any dangling pointers which would trigger a panic. + * Returning non-zero would inform the CC framework that something went wrong + * and it would be unsafe to allow the unload to proceed. However, there is no + * way for this to occur with this implementation so we always return zero. + */ +int +tcp_ccalgounload(struct cc_algo *unload_algo) +{ + struct cc_algo *tmpalgo; + struct inpcb *inp; + struct tcpcb *tp; + VNET_ITERATOR_DECL(vnet_iter); + + /* + * Check all active control blocks across all network stacks and change + * any that are using "unload_algo" back to NewReno. If "unload_algo" + * requires cleanup code to be run, call it. + */ + VNET_LIST_RLOCK(); + VNET_FOREACH(vnet_iter) { + CURVNET_SET(vnet_iter); + INP_INFO_RLOCK(&V_tcbinfo); + /* + * New connections already part way through being initialised + * with the CC algo we're removing will not race with this code + * because the INP_INFO_WLOCK is held during initialisation. We + * therefore don't enter the loop below until the connection + * list has stabilised. + */ + LIST_FOREACH(inp, &V_tcb, inp_list) { + INP_WLOCK(inp); + /* Important to skip tcptw structs. */ + if (!(inp->inp_flags & INP_TIMEWAIT) && + (tp = intotcpcb(inp)) != NULL) { + /* + * By holding INP_WLOCK here, we are assured + * that the connection is not currently + * executing inside the CC module's functions + * i.e. it is safe to make the switch back to + * NewReno. + */ + if (CC_ALGO(tp) == unload_algo) { + tmpalgo = CC_ALGO(tp); + /* NewReno does not require any init. */ + CC_ALGO(tp) = &newreno_cc_algo; + if (tmpalgo->cb_destroy != NULL) + tmpalgo->cb_destroy(tp->ccv); + } + } + INP_WUNLOCK(inp); + } + INP_INFO_RUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + } + VNET_LIST_RUNLOCK(); + + return (0); +} + +/* * Drop a TCP connection, reporting * the specified error. If connection is synchronized, * then send a RST to peer. |
