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improved tcp closure
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robert committed Aug 14, 2023
1 parent 8c03aa2 commit 6c03a81
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Showing 2 changed files with 48 additions and 10 deletions.
29 changes: 24 additions & 5 deletions mongoose.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8122,6 +8122,7 @@ struct mg_tcpip_driver mg_tcpip_driver_w5500 = {w5500_init, w5500_tx, w5500_rx,
#define MIP_TCP_ACK_MS 150 // Timeout for ACKing
#define MIP_TCP_ARP_MS 100 // Timeout for ARP response
#define MIP_TCP_SYN_MS 15000 // Timeout for connection establishment
#define MIP_TCP_FIN_MS 100 // Timeout for closing connection

struct connstate {
uint32_t seq, ack; // TCP seq/ack counters
Expand All @@ -8132,6 +8133,8 @@ struct connstate {
#define MIP_TTYPE_ACK 1 // Peer sent us data, we have to ack it soon
#define MIP_TTYPE_ARP 2 // ARP resolve sent, waiting for response
#define MIP_TTYPE_SYN 3 // SYN sent, waiting for response
#define MIP_TTYPE_FIN 4 // FIN sent, waiting until terminating the connection
#define MIP_TTYPE_CLOSED 5 // Connection is closed
uint8_t tmiss; // Number of keep-alive misses
struct mg_iobuf raw; // For TLS only. Incoming raw data
};
Expand Down Expand Up @@ -8271,6 +8274,7 @@ static void settmout(struct mg_connection *c, uint8_t type) {
unsigned n = type == MIP_TTYPE_ACK ? MIP_TCP_ACK_MS
: type == MIP_TTYPE_ARP ? MIP_TCP_ARP_MS
: type == MIP_TTYPE_SYN ? MIP_TCP_SYN_MS
: type == MIP_TTYPE_FIN ? MIP_TCP_FIN_MS
: MIP_TCP_KEEPALIVE_MS;
s->timer = ifp->now + n;
s->ttype = type;
Expand Down Expand Up @@ -8694,8 +8698,15 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) {
struct mg_iobuf *io = c->is_tls ? &s->raw : &c->recv;
uint32_t seq = mg_ntohl(pkt->tcp->seq);
s->raw.align = c->recv.align;
uint32_t rem_ip;
memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
if (pkt->tcp->flags & TH_FIN) {
s->ack = mg_htonl(pkt->tcp->seq) + 1, s->seq = mg_htonl(pkt->tcp->ack);
if (c->is_closing)
// We initiated FIN so when we receive FIN, we will have to ACK it
tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, TH_ACK,
c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "",
0);
c->is_closing = 1;
} else if (pkt->pay.len == 0) {
// TODO(cpq): handle this peer's ACK
Expand All @@ -8704,8 +8715,6 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) {
if (s->ack == ack) {
MG_VERBOSE(("ignoring duplicate pkt"));
} else {
uint32_t rem_ip;
memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
MG_VERBOSE(("SEQ != ACK: %x %x %x", seq, s->ack, ack));
tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, TH_ACK,
c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "",
Expand Down Expand Up @@ -8973,6 +8982,9 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t uptime_ms) {
mg_error(c, "ARP timeout");
} else if (s->ttype == MIP_TTYPE_SYN) {
mg_error(c, "Connection timeout");
} else if (s->ttype == MIP_TTYPE_FIN) {
s->ttype = MIP_TTYPE_CLOSED;
continue;
} else {
if (s->tmiss++ > 2) {
mg_error(c, "keepalive");
Expand All @@ -8982,6 +8994,7 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t uptime_ms) {
mg_htonl(s->seq - 1), mg_htonl(s->ack), "", 0);
}
}

settmout(c, MIP_TTYPE_KEEPALIVE);
}
}
Expand Down Expand Up @@ -9113,10 +9126,16 @@ static void close_conn(struct mg_connection *c) {
mg_iobuf_free(&s->raw); // For TLS connections, release raw data
if (c->is_udp == false && c->is_listening == false &&
c->is_connecting == false) { // For TCP conns,
struct mg_tcpip_if *ifp =
if (s->ttype != MIP_TTYPE_FIN && s->ttype != MIP_TTYPE_CLOSED) {
struct mg_tcpip_if *ifp =
(struct mg_tcpip_if *) c->mgr->priv; // send TCP FIN
tx_tcp(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);
tx_tcp(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);
} else if (s->ttype == MIP_TTYPE_CLOSED) {
mg_close_conn(c);
}
return;
}
mg_close_conn(c);
}
Expand Down
29 changes: 24 additions & 5 deletions src/tcpip/tcpip.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
#define MIP_TCP_ACK_MS 150 // Timeout for ACKing
#define MIP_TCP_ARP_MS 100 // Timeout for ARP response
#define MIP_TCP_SYN_MS 15000 // Timeout for connection establishment
#define MIP_TCP_FIN_MS 100 // Timeout for closing connection

struct connstate {
uint32_t seq, ack; // TCP seq/ack counters
Expand All @@ -22,6 +23,8 @@ struct connstate {
#define MIP_TTYPE_ACK 1 // Peer sent us data, we have to ack it soon
#define MIP_TTYPE_ARP 2 // ARP resolve sent, waiting for response
#define MIP_TTYPE_SYN 3 // SYN sent, waiting for response
#define MIP_TTYPE_FIN 4 // FIN sent, waiting until terminating the connection
#define MIP_TTYPE_CLOSED 5 // Connection is closed
uint8_t tmiss; // Number of keep-alive misses
struct mg_iobuf raw; // For TLS only. Incoming raw data
};
Expand Down Expand Up @@ -161,6 +164,7 @@ static void settmout(struct mg_connection *c, uint8_t type) {
unsigned n = type == MIP_TTYPE_ACK ? MIP_TCP_ACK_MS
: type == MIP_TTYPE_ARP ? MIP_TCP_ARP_MS
: type == MIP_TTYPE_SYN ? MIP_TCP_SYN_MS
: type == MIP_TTYPE_FIN ? MIP_TCP_FIN_MS
: MIP_TCP_KEEPALIVE_MS;
s->timer = ifp->now + n;
s->ttype = type;
Expand Down Expand Up @@ -584,8 +588,15 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) {
struct mg_iobuf *io = c->is_tls ? &s->raw : &c->recv;
uint32_t seq = mg_ntohl(pkt->tcp->seq);
s->raw.align = c->recv.align;
uint32_t rem_ip;
memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
if (pkt->tcp->flags & TH_FIN) {
s->ack = mg_htonl(pkt->tcp->seq) + 1, s->seq = mg_htonl(pkt->tcp->ack);
if (c->is_closing)
// We initiated FIN so when we receive FIN, we will have to ACK it
tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, TH_ACK,
c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "",
0);
c->is_closing = 1;
} else if (pkt->pay.len == 0) {
// TODO(cpq): handle this peer's ACK
Expand All @@ -594,8 +605,6 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) {
if (s->ack == ack) {
MG_VERBOSE(("ignoring duplicate pkt"));
} else {
uint32_t rem_ip;
memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
MG_VERBOSE(("SEQ != ACK: %x %x %x", seq, s->ack, ack));
tx_tcp((struct mg_tcpip_if *) c->mgr->priv, s->mac, rem_ip, TH_ACK,
c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "",
Expand Down Expand Up @@ -863,6 +872,9 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t uptime_ms) {
mg_error(c, "ARP timeout");
} else if (s->ttype == MIP_TTYPE_SYN) {
mg_error(c, "Connection timeout");
} else if (s->ttype == MIP_TTYPE_FIN) {
s->ttype = MIP_TTYPE_CLOSED;
continue;
} else {
if (s->tmiss++ > 2) {
mg_error(c, "keepalive");
Expand All @@ -872,6 +884,7 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t uptime_ms) {
mg_htonl(s->seq - 1), mg_htonl(s->ack), "", 0);
}
}

settmout(c, MIP_TTYPE_KEEPALIVE);
}
}
Expand Down Expand Up @@ -1003,10 +1016,16 @@ static void close_conn(struct mg_connection *c) {
mg_iobuf_free(&s->raw); // For TLS connections, release raw data
if (c->is_udp == false && c->is_listening == false &&
c->is_connecting == false) { // For TCP conns,
struct mg_tcpip_if *ifp =
if (s->ttype != MIP_TTYPE_FIN && s->ttype != MIP_TTYPE_CLOSED) {
struct mg_tcpip_if *ifp =
(struct mg_tcpip_if *) c->mgr->priv; // send TCP FIN
tx_tcp(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);
tx_tcp(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);
} else if (s->ttype == MIP_TTYPE_CLOSED) {
mg_close_conn(c);
}
return;
}
mg_close_conn(c);
}
Expand Down

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