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Close connection fast if both sides sent FIN
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@cpq
cpq committed Jan 14, 2025
1 parent d386b1c commit fdfa2b7
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Showing 2 changed files with 26 additions and 6 deletions.
16 changes: 13 additions & 3 deletions mongoose.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4108,6 +4108,8 @@ struct connstate {
#define MIP_TTYPE_FIN 4 // FIN sent, waiting until terminating the connection
uint8_t tmiss; // Number of keep-alive misses
struct mg_iobuf raw; // For TLS only. Incoming raw data
bool fin_sent; // We have sent FIN to the peer
bool fin_rcvd; // We have received FIN from the peer
};

#pragma pack(push, 1)
Expand Down Expand Up @@ -4722,7 +4724,7 @@ long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
}

static void handle_tls_recv(struct mg_connection *c) {
size_t avail = mg_tls_pending(c);
size_t avail = mg_tls_pending(c);
size_t min = avail > MG_MAX_RECV_SIZE ? MG_MAX_RECV_SIZE : avail;
struct mg_iobuf *io = &c->recv;
if (io->size - io->len < min && !mg_iobuf_resize(io, io->len + min)) {
Expand All @@ -4736,7 +4738,7 @@ static void handle_tls_recv(struct mg_connection *c) {
// Decrypted successfully - trigger MG_EV_READ
io->len += (size_t) n;
mg_call(c, MG_EV_READ, &n);
} // else n < 0: outstanding data to be moved to c->recv
} // else n < 0: outstanding data to be moved to c->recv
}
}

Expand All @@ -4752,21 +4754,28 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) {
// closure process
uint8_t flags = TH_ACK;
s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len + 1);
s->fin_rcvd = true;
if (c->is_draining && s->ttype == MIP_TTYPE_FIN) {
if (s->seq == mg_htonl(pkt->tcp->ack)) { // Simultaneous closure ?
s->seq++; // Yes. Increment our SEQ
} else { // Otherwise,
s->seq = mg_htonl(pkt->tcp->ack); // Set to peer's ACK
}
if (s->fin_sent) c->is_closing = 1; // Both sides closed, we're done
} else {
flags |= TH_FIN;
c->is_draining = 1;
s->fin_sent = true;
settmout(c, MIP_TTYPE_FIN);
}
tx_tcp(c->mgr->ifp, s->mac, rem_ip, flags, c->loc.port, c->rem.port,
mg_htonl(s->seq), mg_htonl(s->ack), "", 0);
} else if (pkt->pay.len == 0) {
// TODO(cpq): handle this peer's ACK
// If we receive a final ACK in TCP closure, close immediately,
// don't wait until MIP_TTYPE_FIN timeout expires
if (s->fin_rcvd && s->fin_sent) {
c->is_closing = true;
}
} else if (seq != s->ack) {
uint32_t ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len);
if (s->ack == ack) {
Expand Down Expand Up @@ -5213,6 +5222,7 @@ static void init_closure(struct mg_connection *c) {
tx_tcp(c->mgr->ifp, s->mac, rem_ip, TH_FIN | TH_ACK, c->loc.port,
c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0);
settmout(c, MIP_TTYPE_FIN);
s->fin_sent = true;
}
}

Expand Down
16 changes: 13 additions & 3 deletions src/net_builtin.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,8 @@ struct connstate {
#define MIP_TTYPE_FIN 4 // FIN sent, waiting until terminating the connection
uint8_t tmiss; // Number of keep-alive misses
struct mg_iobuf raw; // For TLS only. Incoming raw data
bool fin_sent; // We have sent FIN to the peer
bool fin_rcvd; // We have received FIN from the peer
};

#pragma pack(push, 1)
Expand Down Expand Up @@ -642,7 +644,7 @@ long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
}

static void handle_tls_recv(struct mg_connection *c) {
size_t avail = mg_tls_pending(c);
size_t avail = mg_tls_pending(c);
size_t min = avail > MG_MAX_RECV_SIZE ? MG_MAX_RECV_SIZE : avail;
struct mg_iobuf *io = &c->recv;
if (io->size - io->len < min && !mg_iobuf_resize(io, io->len + min)) {
Expand All @@ -656,7 +658,7 @@ static void handle_tls_recv(struct mg_connection *c) {
// Decrypted successfully - trigger MG_EV_READ
io->len += (size_t) n;
mg_call(c, MG_EV_READ, &n);
} // else n < 0: outstanding data to be moved to c->recv
} // else n < 0: outstanding data to be moved to c->recv
}
}

Expand All @@ -672,21 +674,28 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) {
// closure process
uint8_t flags = TH_ACK;
s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len + 1);
s->fin_rcvd = true;
if (c->is_draining && s->ttype == MIP_TTYPE_FIN) {
if (s->seq == mg_htonl(pkt->tcp->ack)) { // Simultaneous closure ?
s->seq++; // Yes. Increment our SEQ
} else { // Otherwise,
s->seq = mg_htonl(pkt->tcp->ack); // Set to peer's ACK
}
if (s->fin_sent) c->is_closing = 1; // Both sides closed, we're done
} else {
flags |= TH_FIN;
c->is_draining = 1;
s->fin_sent = true;
settmout(c, MIP_TTYPE_FIN);
}
tx_tcp(c->mgr->ifp, s->mac, rem_ip, flags, c->loc.port, c->rem.port,
mg_htonl(s->seq), mg_htonl(s->ack), "", 0);
} else if (pkt->pay.len == 0) {
// TODO(cpq): handle this peer's ACK
// If we receive a final ACK in TCP closure, close immediately,
// don't wait until MIP_TTYPE_FIN timeout expires
if (s->fin_rcvd && s->fin_sent) {
c->is_closing = true;
}
} else if (seq != s->ack) {
uint32_t ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len);
if (s->ack == ack) {
Expand Down Expand Up @@ -1133,6 +1142,7 @@ static void init_closure(struct mg_connection *c) {
tx_tcp(c->mgr->ifp, s->mac, rem_ip, TH_FIN | TH_ACK, c->loc.port,
c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0);
settmout(c, MIP_TTYPE_FIN);
s->fin_sent = true;
}
}

Expand Down

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