nihilist/tor
1
0
Fork 0
mirror of https://gitlab.torproject.org/tpo/core/tor.git synced 2024-11-10 21:23:58 +01:00
Code Issues Packages Projects Releases Wiki Activity

sched: Fallback to naive approach if no runtime KIST support

Browse Source 
It is possible that tor was compiled with KIST support but the running kernel
has no support for it. In that case, fallback to a naive approach and flag
that we have no kernel support.

At this commit, if the kernel support is disabled, there are no ways to come
back from it other than restarting tor with a kernel that supporst KIST.

Signed-off-by: David Goulet <dgoulet@torproject.org>
This commit is contained in:
David Goulet 2017-08-31 10:41:14 -04:00
parent 8424c4f35b
commit a06f2a0509
1 changed files with 36 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/or/scheduler_kist.c
View File

@ -24,6 +24,11 @@
* Data structures and supporting functions
*****************************************************************************/
/* Indicate if we don't have the kernel support. This can happen if the kernel
* changed and it doesn't recognized the values passed to the syscalls needed
* by KIST. In that case, fallback to the naive approach. */
static unsigned int kist_no_kernel_support = 0;
/* Socket_table hash table stuff. The socket_table keeps track of per-socket
* limit information imposed by kist and used by kist. */
@ -174,9 +179,34 @@ update_socket_info_impl, (socket_table_ent_t *ent))
struct tcp_info tcp;
socklen_t tcp_info_len = sizeof(tcp);
if (kist_no_kernel_support) {
goto fallback;
}
/* Gather information */
getsockopt(sock, SOL_TCP, TCP_INFO, (void *)&(tcp), &tcp_info_len);
ioctl(sock, SIOCOUTQNSD, &(ent->notsent));
if (getsockopt(sock, SOL_TCP, TCP_INFO, (void *)&(tcp), &tcp_info_len) < 0) {
if (errno == EINVAL) {
/* Oops, this option is not provided by the kernel, we'll have to
* disable KIST entirely. This can happen if tor was built on a machine
* with the support previously or if the kernel was updated and lost the
* support. */
log_notice(LD_SCHED, "Looks like our kernel doesn't have the support "
"for KIST anymore. Fallback to the naive approach. "
"Set KISTSchedRunInterval=-1 to disable KIST.");
kist_no_kernel_support = 1;
}
goto fallback;
}
if (ioctl(sock, SIOCOUTQNSD, &(ent->notsent)) < 0) {
if (errno == EINVAL) {
log_notice(LD_SCHED, "Looks like our kernel doesn't have the support "
"for KIST anymore. Fallback to the naive approach. "
"Set KISTSchedRunInterval=-1 to disable KIST.");
/* Same reason as the above. */
kist_no_kernel_support = 1;
}
goto fallback;
}
ent->cwnd = tcp.tcpi_snd_cwnd;
ent->unacked = tcp.tcpi_unacked;
ent->mss = tcp.tcpi_snd_mss;
@ -193,6 +223,10 @@ update_socket_info_impl, (socket_table_ent_t *ent))
}
ent->limit = tcp_space + extra_space;
return;
fallback:
ent->cwnd = ent->unacked = ent->mss = ent->notsent = 0;
ent->limit = INT_MAX;
}
/* Given a socket that isn't in the table, add it.