From 1bf5ce5ccb6ae383fc226f4bd2c9e85da5868676 Mon Sep 17 00:00:00 2001 From: Sergey Lyubka Date: Sat, 2 Mar 2024 21:11:37 +0000 Subject: [PATCH] Better acks --- mongoose.c | 40 ++++++++++++++++++++++++++++------------ src/net_builtin.c | 42 ++++++++++++++++++++++++++++-------------- 2 files changed, 56 insertions(+), 26 deletions(-) diff --git a/mongoose.c b/mongoose.c index bd1593d9b76..3cc6492f955 100644 --- a/mongoose.c +++ b/mongoose.c @@ -4894,12 +4894,13 @@ void mg_mgr_init(struct mg_mgr *mgr) { #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 1000 // Timeout for closing connection -#define MIP_TCP_WIN 16384 // TCP window size +#define MIP_TCP_WIN 6000 // TCP window size struct connstate { uint32_t seq, ack; // TCP seq/ack counters uint64_t timer; // TCP keep-alive / ACK timer - size_t noack; // Not ACK-ed received TCP bytes + uint32_t acked; // Last ACK-ed number + size_t unacked; // Not acked bytes uint8_t mac[6]; // Peer MAC address uint8_t ttype; // Timer type. 0: ack, 1: keep-alive #define MIP_TTYPE_KEEPALIVE 0 // Connection is idle for long, send keepalive @@ -5371,6 +5372,14 @@ static void rx_udp(struct mg_tcpip_if *ifp, struct pkt *pkt) { static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip, uint8_t flags, uint16_t sport, uint16_t dport, uint32_t seq, uint32_t ack, const void *buf, size_t len) { +#if 0 + uint8_t opts[] = {2, 4, 5, 0xb4, 4, 2, 0, 0}; // MSS = 1460, SACK permitted + if (flags & TH_SYN) { + // Handshake? Set MSS + buf = opts; + len = sizeof(opts); + } +#endif struct ip *ip = tx_ip(ifp, dst_mac, 6, ifp->ip, dst_ip, sizeof(struct tcp) + len); struct tcp *tcp = (struct tcp *) (ip + 1); @@ -5383,6 +5392,8 @@ static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip, tcp->flags = flags; tcp->win = mg_htons(MIP_TCP_WIN); tcp->off = (uint8_t) (sizeof(*tcp) / 4 << 4); + // if (flags & TH_SYN) tcp->off = 0x70; // Handshake? header size 28 bytes + uint32_t cs = 0; uint16_t n = (uint16_t) (sizeof(*tcp) + len); uint8_t pseudo[] = {0, ip->proto, (uint8_t) (n >> 8), (uint8_t) (n & 255)}; @@ -5393,7 +5404,7 @@ static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip, tcp->csum = csumfin(cs); MG_VERBOSE(("TCP %M:%hu -> %M:%hu fl %x len %u", mg_print_ip4, &ip->src, mg_ntohs(tcp->sport), mg_print_ip4, &ip->dst, - mg_ntohs(tcp->dport), tcp->flags, (int) len)); + mg_ntohs(tcp->dport), tcp->flags, len)); // mg_hexdump(ifp->tx.ptr, PDIFF(ifp->tx.ptr, tcp + 1) + len); return ether_output(ifp, PDIFF(ifp->tx.ptr, tcp + 1) + len); } @@ -5512,6 +5523,7 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) { } else if (pkt->pay.len == 0) { // TODO(cpq): handle this peer's ACK } else if (seq != s->ack) { +#if 0 uint32_t ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len); if (s->ack == ack) { MG_VERBOSE(("ignoring duplicate pkt")); @@ -5521,6 +5533,7 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) { c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "", 0); } +#endif } else if (io->size - io->len < pkt->pay.len && !mg_iobuf_resize(io, io->len + pkt->pay.len)) { mg_error(c, "oom"); @@ -5536,14 +5549,17 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) { MG_VERBOSE(("%lu SEQ %x -> %x", c->id, mg_htonl(pkt->tcp->seq), s->ack)); // Advance ACK counter s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len); - s->noack += pkt->pay.len; - if (s->noack + 1500 >= MIP_TCP_WIN) { + s->unacked += pkt->pay.len; + // size_t diff = s->acked <= s->ack ? s->ack - s->acked : s->ack; + if (s->unacked > MIP_TCP_WIN / 2 && s->acked != s->ack) { // Send ACK immediately - MG_VERBOSE((" imm ACK", c->id, mg_htonl(pkt->tcp->seq), s->ack)); + MG_VERBOSE(("%lu imm ACK %lu", c->id, s->acked)); 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), "", + c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0); - s->noack = 0; + s->unacked = 0; + s->acked = s->ack; + if (s->ttype != MIP_TTYPE_KEEPALIVE) settmout(c, MIP_TTYPE_KEEPALIVE); } else { // if not already running, setup a timer to send an ACK later if (s->ttype != MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_ACK); @@ -5787,11 +5803,11 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) { uint32_t rem_ip; memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t)); if (now > s->timer) { - if (s->ttype == MIP_TTYPE_ACK) { + if (s->ttype == MIP_TTYPE_ACK && s->acked != s->ack) { MG_VERBOSE(("%lu ack %x %x", c->id, s->seq, s->ack)); tx_tcp(ifp, s->mac, rem_ip, TH_ACK, c->loc.port, c->rem.port, - mg_htonl(s->seq), mg_htonl(s->ack), "", 0); - s->noack = 0; + mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0); + s->acked = s->ack; } else if (s->ttype == MIP_TTYPE_ARP) { mg_error(c, "ARP timeout"); } else if (s->ttype == MIP_TTYPE_SYN) { @@ -5805,7 +5821,7 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) { } else { MG_VERBOSE(("%lu keepalive", c->id)); tx_tcp(ifp, s->mac, rem_ip, TH_ACK, c->loc.port, c->rem.port, - mg_htonl(s->seq - 1), mg_htonl(s->ack), "", 0); + mg_htonl(s->seq - 1), mg_htonl(s->ack), NULL, 0); } } diff --git a/src/net_builtin.c b/src/net_builtin.c index ab862f02040..80d4957e3b5 100644 --- a/src/net_builtin.c +++ b/src/net_builtin.c @@ -12,12 +12,13 @@ #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 1000 // Timeout for closing connection -#define MIP_TCP_WIN 16384 // TCP window size +#define MIP_TCP_WIN 6000 // TCP window size struct connstate { uint32_t seq, ack; // TCP seq/ack counters uint64_t timer; // TCP keep-alive / ACK timer - size_t noack; // Not ACK-ed received TCP bytes + uint32_t acked; // Last ACK-ed number + size_t unacked; // Not acked bytes uint8_t mac[6]; // Peer MAC address uint8_t ttype; // Timer type. 0: ack, 1: keep-alive #define MIP_TTYPE_KEEPALIVE 0 // Connection is idle for long, send keepalive @@ -489,6 +490,14 @@ static void rx_udp(struct mg_tcpip_if *ifp, struct pkt *pkt) { static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip, uint8_t flags, uint16_t sport, uint16_t dport, uint32_t seq, uint32_t ack, const void *buf, size_t len) { +#if 0 + uint8_t opts[] = {2, 4, 5, 0xb4, 4, 2, 0, 0}; // MSS = 1460, SACK permitted + if (flags & TH_SYN) { + // Handshake? Set MSS + buf = opts; + len = sizeof(opts); + } +#endif struct ip *ip = tx_ip(ifp, dst_mac, 6, ifp->ip, dst_ip, sizeof(struct tcp) + len); struct tcp *tcp = (struct tcp *) (ip + 1); @@ -501,6 +510,8 @@ static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip, tcp->flags = flags; tcp->win = mg_htons(MIP_TCP_WIN); tcp->off = (uint8_t) (sizeof(*tcp) / 4 << 4); + // if (flags & TH_SYN) tcp->off = 0x70; // Handshake? header size 28 bytes + uint32_t cs = 0; uint16_t n = (uint16_t) (sizeof(*tcp) + len); uint8_t pseudo[] = {0, ip->proto, (uint8_t) (n >> 8), (uint8_t) (n & 255)}; @@ -511,7 +522,7 @@ static size_t tx_tcp(struct mg_tcpip_if *ifp, uint8_t *dst_mac, uint32_t dst_ip, tcp->csum = csumfin(cs); MG_VERBOSE(("TCP %M:%hu -> %M:%hu fl %x len %u", mg_print_ip4, &ip->src, mg_ntohs(tcp->sport), mg_print_ip4, &ip->dst, - mg_ntohs(tcp->dport), tcp->flags, (int) len)); + mg_ntohs(tcp->dport), tcp->flags, len)); // mg_hexdump(ifp->tx.ptr, PDIFF(ifp->tx.ptr, tcp + 1) + len); return ether_output(ifp, PDIFF(ifp->tx.ptr, tcp + 1) + len); } @@ -630,6 +641,7 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) { } else if (pkt->pay.len == 0) { // TODO(cpq): handle this peer's ACK } else if (seq != s->ack) { +#if 0 uint32_t ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len); if (s->ack == ack) { MG_VERBOSE(("ignoring duplicate pkt")); @@ -639,6 +651,7 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) { c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), "", 0); } +#endif } else if (io->size - io->len < pkt->pay.len && !mg_iobuf_resize(io, io->len + pkt->pay.len)) { mg_error(c, "oom"); @@ -654,16 +667,17 @@ static void read_conn(struct mg_connection *c, struct pkt *pkt) { MG_VERBOSE(("%lu SEQ %x -> %x", c->id, mg_htonl(pkt->tcp->seq), s->ack)); // Advance ACK counter s->ack = (uint32_t) (mg_htonl(pkt->tcp->seq) + pkt->pay.len); - s->noack += pkt->pay.len; - if (s->noack + 1500 >= MIP_TCP_WIN) { + s->unacked += pkt->pay.len; + // size_t diff = s->acked <= s->ack ? s->ack - s->acked : s->ack; + if (s->unacked > MIP_TCP_WIN / 2 && s->acked != s->ack) { // Send ACK immediately - MG_VERBOSE((" imm ACK", c->id, mg_htonl(pkt->tcp->seq), s->ack)); + MG_VERBOSE(("%lu imm ACK %lu", c->id, s->acked)); 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), "", + c->loc.port, c->rem.port, mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0); - s->noack = 0; - // restart the ACK timer if already running - if (s->ttype == MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_ACK); + s->unacked = 0; + s->acked = s->ack; + if (s->ttype != MIP_TTYPE_KEEPALIVE) settmout(c, MIP_TTYPE_KEEPALIVE); } else { // if not already running, setup a timer to send an ACK later if (s->ttype != MIP_TTYPE_ACK) settmout(c, MIP_TTYPE_ACK); @@ -907,11 +921,11 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) { uint32_t rem_ip; memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t)); if (now > s->timer) { - if (s->ttype == MIP_TTYPE_ACK) { + if (s->ttype == MIP_TTYPE_ACK && s->acked != s->ack) { MG_VERBOSE(("%lu ack %x %x", c->id, s->seq, s->ack)); tx_tcp(ifp, s->mac, rem_ip, TH_ACK, c->loc.port, c->rem.port, - mg_htonl(s->seq), mg_htonl(s->ack), "", 0); - s->noack = 0; + mg_htonl(s->seq), mg_htonl(s->ack), NULL, 0); + s->acked = s->ack; } else if (s->ttype == MIP_TTYPE_ARP) { mg_error(c, "ARP timeout"); } else if (s->ttype == MIP_TTYPE_SYN) { @@ -925,7 +939,7 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) { } else { MG_VERBOSE(("%lu keepalive", c->id)); tx_tcp(ifp, s->mac, rem_ip, TH_ACK, c->loc.port, c->rem.port, - mg_htonl(s->seq - 1), mg_htonl(s->ack), "", 0); + mg_htonl(s->seq - 1), mg_htonl(s->ack), NULL, 0); } }