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Merge pull request #3009 from cesanta/fin
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Close connection fast if both sides sent FIN
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@scaprile
scaprile authored Jan 17, 2025
2 parents 8dbfcbf + 091356e commit 74b3fd2
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Showing 2 changed files with 30 additions and 10 deletions.
20 changes: 15 additions & 5 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_rcvd; // We have received FIN from the peer
bool twclosure; // 3-way closure done
};

#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 +4754,24 @@ 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
}
s->twclosure = true;
} else {
flags |= TH_FIN;
c->is_draining = 1;
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
} else if (pkt->pay.len == 0) { // this is an ACK
if (s->fin_rcvd && s->ttype == MIP_TTYPE_FIN)
s->twclosure = 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 @@ -5052,7 +5057,7 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) {
struct connstate *s = (struct connstate *) (c + 1);
uint32_t rem_ip;
memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
if (now > s->timer) {
if (ifp->now > s->timer) {
if (s->ttype == MIP_TTYPE_ARP) {
mg_error(c, "ARP timeout");
} else if (c->is_udp) {
Expand Down Expand Up @@ -5240,10 +5245,15 @@ void mg_mgr_poll(struct mg_mgr *mgr, int ms) {
MG_VERBOSE(("%lu .. %c%c%c%c%c", c->id, c->is_tls ? 'T' : 't',
c->is_connecting ? 'C' : 'c', c->is_tls_hs ? 'H' : 'h',
c->is_resolving ? 'R' : 'r', c->is_closing ? 'C' : 'c'));
// order is important, TLS conn close with > 1 record in buffer
if (c->is_tls && mg_tls_pending(c) > 0) handle_tls_recv(c);
if (can_write(c)) write_conn(c);
if (c->is_draining && c->send.len == 0 && s->ttype != MIP_TTYPE_FIN)
init_closure(c);
// For non-TLS, close immediately upon completing the 3-way closure
// For TLS, process any pending data until MIP_TTYPE_FIN timeout expires
if (s->twclosure && (!c->is_tls || mg_tls_pending(c) == 0))
c->is_closing = 1;
if (c->is_closing) close_conn(c);
}
(void) ms;
Expand Down
20 changes: 15 additions & 5 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_rcvd; // We have received FIN from the peer
bool twclosure; // 3-way closure done
};

#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 +674,24 @@ 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
}
s->twclosure = true;
} else {
flags |= TH_FIN;
c->is_draining = 1;
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
} else if (pkt->pay.len == 0) { // this is an ACK
if (s->fin_rcvd && s->ttype == MIP_TTYPE_FIN)
s->twclosure = 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 @@ -972,7 +977,7 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) {
struct connstate *s = (struct connstate *) (c + 1);
uint32_t rem_ip;
memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
if (now > s->timer) {
if (ifp->now > s->timer) {
if (s->ttype == MIP_TTYPE_ARP) {
mg_error(c, "ARP timeout");
} else if (c->is_udp) {
Expand Down Expand Up @@ -1160,10 +1165,15 @@ void mg_mgr_poll(struct mg_mgr *mgr, int ms) {
MG_VERBOSE(("%lu .. %c%c%c%c%c", c->id, c->is_tls ? 'T' : 't',
c->is_connecting ? 'C' : 'c', c->is_tls_hs ? 'H' : 'h',
c->is_resolving ? 'R' : 'r', c->is_closing ? 'C' : 'c'));
// order is important, TLS conn close with > 1 record in buffer
if (c->is_tls && mg_tls_pending(c) > 0) handle_tls_recv(c);
if (can_write(c)) write_conn(c);
if (c->is_draining && c->send.len == 0 && s->ttype != MIP_TTYPE_FIN)
init_closure(c);
// For non-TLS, close immediately upon completing the 3-way closure
// For TLS, process any pending data until MIP_TTYPE_FIN timeout expires
if (s->twclosure && (!c->is_tls || mg_tls_pending(c) == 0))
c->is_closing = 1;
if (c->is_closing) close_conn(c);
}
(void) ms;
Expand Down

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