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Merge MTU probing with failover

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This commit also fixes MTU probing in some corner cases.

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>
This commit is contained in:
Adrien Gallouët
2019-03-05 11:05:36 +00:00
parent adf3bf6710
commit bb60f5f15f
2 changed files with 41 additions and 50 deletions
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88
mud.c
View File

@@ -64,7 +64,7 @@
#define MUD_MSG(X) ((X) & UINT64_C(1))
#define MUD_MSG_MARK(X) ((X) | UINT64_C(1))
#define MUD_MSG_TC (192) // CS6
#define MUD_MSG_SENT_MAX (10)
#define MUD_MSG_SENT_MAX (3)
#define MUD_MSG_MIN_RTT (100 * MUD_ONE_MSEC)
#define MUD_PKT_MIN_SIZE (MUD_U48_SIZE + MUD_MAC_SIZE)
@@ -545,10 +545,6 @@ mud_update_rate(struct mud *mud, struct mud_path *path, uint64_t rate)
static void
mud_reset_path(struct mud *mud, struct mud_path *path)
{
path->mtu.ok = MUD_MTU_MIN;
path->mtu.min = MUD_MTU_MIN;
path->mtu.max = MUD_MTU_MAX;
path->mtu.count = 0;
path->window = 0;
path->ok = 0;
path->msg_sent = 0;
@@ -612,6 +608,12 @@ mud_get_path(struct mud *mud, struct sockaddr_storage *local_addr,
memcpy(&path->addr, addr, sizeof(*addr));
path->state = MUD_UP;
path->mtu.ok = MUD_MTU_MIN;
path->mtu.min = MUD_MTU_MIN;
path->mtu.max = MUD_MTU_MAX;
path->mtu.probe = MUD_MTU_MAX;
mud_reset_path(mud, path);
return path;
@@ -1242,10 +1244,14 @@ mud_recv_msg(struct mud *mud, struct mud_path *path,
const uint64_t peer_sent = mud_read48(msg->sent);
if (peer_sent) {
if (path->mtu.ok < size) {
path->mtu.ok = size;
path->mtu.min = size + 1;
path->mtu.count = 0;
path->mtu.min = size + 1;
path->mtu.ok = size;
if (!path->ok) {
path->mtu.max = MUD_MTU_MAX;
path->mtu.probe = MUD_MTU_MAX;
} else {
path->mtu.probe = (path->mtu.min + path->mtu.max) >> 1;
}
mud_update_stat(&path->rtt, MUD_TIME_MASK(now - peer_sent));
@@ -1394,35 +1400,6 @@ mud_path_timeout(struct mud_path *path)
return rtt > MUD_MSG_MIN_RTT ? rtt : MUD_MSG_MIN_RTT;
}
static void
mud_probe_mtu(struct mud *mud, struct mud_path *path, uint64_t now)
{
if (path->mtu.min > path->mtu.max)
return;
if (path->mtu.count &&
!mud_timeout(now, path->mtu.time, mud_path_timeout(path)))
return;
path->mtu.time = now;
while (1) {
const size_t probe = (path->mtu.min + path->mtu.max) >> 1;
if (path->mtu.count == 2) {
path->mtu.max = probe - 1;
path->mtu.count = 0;
continue;
}
path->mtu.count++;
if ((mud_send_msg(mud, path, now, 0, 0, 0, probe) != -1) ||
(errno != EMSGSIZE))
break;
}
}
static void
mud_update(struct mud *mud, uint64_t now)
{
@@ -1442,19 +1419,34 @@ mud_update(struct mud *mud, uint64_t now)
if (path->state <= MUD_DOWN)
continue;
if (path->ok) {
if (path->msg_sent >= MUD_MSG_SENT_MAX || (path->recv.time &&
mud->last_recv_time > path->recv.time + MUD_ONE_SEC)) {
mud_reset_path(mud, path);
} else {
if (!mtu || mtu > path->mtu.ok)
mtu = path->mtu.ok;
if (mud->peer.set) {
if (path->msg_sent >= MUD_MSG_SENT_MAX) {
if (path->mtu.probe == MUD_MTU_MIN) {
mud_reset_path(mud, path);
} else {
if (path->mtu.ok == path->mtu.probe) {
path->mtu.min = MUD_MTU_MIN;
path->mtu.ok = MUD_MTU_MIN;
mud_reset_path(mud, path);
} else {
path->msg_sent = 0;
}
path->mtu.max = path->mtu.probe - 1;
path->mtu.probe = (path->mtu.min + path->mtu.max) >> 1;
}
}
} else {
if ((path->msg_sent >= MUD_MSG_SENT_MAX) ||
(path->recv.time &&
mud->last_recv_time > path->recv.time + MUD_ONE_SEC)) {
mud_reset_path(mud, path);
}
if (mud->peer.set)
mud_probe_mtu(mud, path, now);
}
if (path->ok) {
if (!mtu || mtu > path->mtu.ok) {
mtu = path->mtu.ok;
}
if (mud_timeout(now, path->window_time, MUD_WINDOW_TIMEOUT)) {
path->window = path->window_size;
path->window_time = now;
@@ -1465,7 +1457,7 @@ mud_update(struct mud *mud, uint64_t now)
if (mud->peer.set) {
if (mud_timeout(now, path->send.msg_time, mud_path_timeout(path)))
mud_send_msg(mud, path, now, 0, 0, 0, 0);
mud_send_msg(mud, path, now, 0, 0, 0, path->mtu.probe);
}
window += path->window;

3
mud.h
View File

@@ -38,9 +38,8 @@ struct mud_path {
struct {
size_t min;
size_t max;
size_t probe;
size_t ok;
uint64_t time;
unsigned char count;
} mtu;
struct {
uint64_t total;