/*
utcp.c -- Userspace TCP
- Copyright (C) 2014 Guus Sliepen <guus@tinc-vpn.org>
+ Copyright (C) 2014-2017 Guus Sliepen <guus@tinc-vpn.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
}
memcpy(&hdr, pkt, sizeof hdr);
- debug("%p %s: len=%lu, src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, (unsigned long)len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
+ debug("%p %s: len=%lu, src=%u dst=%u seq=%u ack=%u wnd=%u aux=%x ctl=", utcp, dir, (unsigned long)len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd, hdr.aux);
if(hdr.ctl & SYN)
debug("SYN");
if(hdr.ctl & RST)
debug("\n");
}
#else
-#define debug(...)
-#define print_packet(...)
+#define debug(...) do {} while(0)
+#define print_packet(...) do {} while(0)
#endif
static void set_state(struct utcp_connection *c, enum state state) {
return c->flags & UTCP_RELIABLE;
}
-static inline void list_connections(struct utcp *utcp) {
- debug("%p has %d connections:\n", utcp, utcp->nconnections);
- for(int i = 0; i < utcp->nconnections; i++)
- debug(" %u -> %u state %s\n", utcp->connections[i]->src, utcp->connections[i]->dst, strstate[utcp->connections[i]->state]);
-}
-
static int32_t seqdiff(uint32_t a, uint32_t b) {
return a - b;
}
return c;
}
+static inline uint32_t absdiff(uint32_t a, uint32_t b) {
+ if(a > b)
+ return a - b;
+ else
+ return b - a;
+}
+
// Update RTT variables. See RFC 6298.
static void update_rtt(struct utcp_connection *c, uint32_t rtt) {
if(!rtt) {
utcp->rttvar = rtt / 2;
utcp->rto = rtt + max(2 * rtt, CLOCK_GRANULARITY);
} else {
- utcp->rttvar = (utcp->rttvar * 3 + abs(utcp->srtt - rtt)) / 4;
+ utcp->rttvar = (utcp->rttvar * 3 + absdiff(utcp->srtt, rtt)) / 4;
utcp->srtt = (utcp->srtt * 7 + rtt) / 8;
utcp->rto = utcp->srtt + max(utcp->rttvar, CLOCK_GRANULARITY);
}
gettimeofday(&c->conn_timeout, NULL);
c->conn_timeout.tv_sec += utcp->timeout;
+ start_retransmit_timer(c);
+
return c;
}
struct {
struct hdr hdr;
- char data[];
+ uint8_t data[];
} *pkt;
pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
struct {
struct hdr hdr;
- char data[];
+ uint8_t data[];
} *pkt;
pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
pkt->hdr.seq = c->snd.iss;
pkt->hdr.ack = 0;
pkt->hdr.ctl = SYN;
- print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
- utcp->send(utcp, pkt, sizeof pkt->hdr);
+ pkt->hdr.aux = 0x0101;
+ pkt->data[0] = 1;
+ pkt->data[1] = 0;
+ pkt->data[2] = 0;
+ pkt->data[3] = c->flags & 0x7;
+ print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + 4);
+ utcp->send(utcp, pkt, sizeof pkt->hdr + 4);
break;
case SYN_RECEIVED:
debug("out of order packet, offset %u\n", offset);
// Packet loss or reordering occured. Store the data in the buffer.
ssize_t rxd = buffer_put_at(&c->rcvbuf, offset, data, len);
- if(rxd < len)
+ if(rxd < 0 || (size_t)rxd < len)
abort();
// Make note of where we put it.
if(c->recv) {
ssize_t rxd = c->recv(c, data, len);
- if(rxd != len) {
+ if(rxd < 0 || (size_t)rxd != len) {
// TODO: handle the application not accepting all data.
abort();
}
return -1;
}
+ // Check for auxiliary headers
+
+ const uint8_t *init = NULL;
+
+ uint16_t aux = hdr.aux;
+ while(aux) {
+ size_t auxlen = 4 * (aux >> 8) & 0xf;
+ uint8_t auxtype = aux & 0xff;
+
+ if(len < auxlen) {
+ errno = EBADMSG;
+ return -1;
+ }
+
+ switch(auxtype) {
+ case AUX_INIT:
+ if(!(hdr.ctl & SYN) || auxlen != 4) {
+ errno = EBADMSG;
+ return -1;
+ }
+ init = data;
+ break;
+ default:
+ errno = EBADMSG;
+ return -1;
+ }
+
+ len -= auxlen;
+ data += auxlen;
+
+ if(!(aux & 0x800))
+ break;
+
+ if(len < 2) {
+ errno = EBADMSG;
+ return -1;
+ }
+
+ memcpy(&aux, data, 2);
+ len -= 2;
+ data += 2;
+ }
+
// Try to match the packet to an existing connection
struct utcp_connection *c = find_connection(utcp, hdr.dst, hdr.src);
}
// Parse auxilliary information
- if(hdr.aux) {
- if(hdr.aux != 0x0101 || len < 4 || ((uint8_t *)data)[0] != 1) {
+ if(init) {
+ if(init[0] < 1) {
len = 1;
goto reset;
}
- c->flags = ((uint8_t *)data)[3] & 0x7;
- data += 4;
- len -= 4;
+ c->flags = init[3] & 0x7;
} else {
c->flags = UTCP_TCP;
}
c->rcv.nxt = c->rcv.irs + 1;
set_state(c, SYN_RECEIVED);
- hdr.dst = c->dst;
- hdr.src = c->src;
- hdr.ack = c->rcv.irs + 1;
- hdr.seq = c->snd.iss;
- hdr.ctl = SYN | ACK;
- print_packet(c->utcp, "send", &hdr, sizeof hdr);
- utcp->send(utcp, &hdr, sizeof hdr);
+ struct {
+ struct hdr hdr;
+ uint8_t data[4];
+ } pkt;
+
+ pkt.hdr.src = c->src;
+ pkt.hdr.dst = c->dst;
+ pkt.hdr.ack = c->rcv.irs + 1;
+ pkt.hdr.seq = c->snd.iss;
+ pkt.hdr.wnd = c->rcv.wnd;
+ pkt.hdr.ctl = SYN | ACK;
+ if(init) {
+ pkt.hdr.aux = 0x0101;
+ pkt.data[0] = 1;
+ pkt.data[1] = 0;
+ pkt.data[2] = 0;
+ pkt.data[3] = c->flags & 0x7;
+ print_packet(c->utcp, "send", &pkt, sizeof hdr + 4);
+ utcp->send(utcp, &pkt, sizeof hdr + 4);
+ } else {
+ pkt.hdr.aux = 0;
+ print_packet(c->utcp, "send", &pkt, sizeof hdr);
+ utcp->send(utcp, &pkt, sizeof hdr);
+ }
} else {
// No, we don't want your packets, send a RST back
len = 1;
// cut already accepted front overlapping
if(rcv_offset < 0) {
- acceptable = len > -rcv_offset;
+ acceptable = len > (size_t)-rcv_offset;
if(acceptable) {
data -= rcv_offset;
len += rcv_offset;
}
}
+ if(!(hdr.ctl & ACK))
+ goto skip_ack;
+
// 3. Advance snd.una
uint32_t advanced = seqdiff(hdr.ack, c->snd.una);
start_retransmit_timer(c);
}
+skip_ack:
// 5. Process SYN stuff
if(hdr.ctl & SYN) {
case LAST_ACK:
case TIME_WAIT:
// Ehm, no. We should never receive a second SYN.
- goto reset;
+ return 0;
default:
#ifdef UTCP_DEBUG
abort();
reset:
swap_ports(&hdr);
hdr.wnd = 0;
+ hdr.aux = 0;
if(hdr.ctl & ACK) {
hdr.seq = hdr.ack;
hdr.ctl = RST;
if(!utcp)
return;
for(int i = 0; i < utcp->nconnections; i++) {
- if(!utcp->connections[i]->reapable)
- debug("Warning, freeing unclosed connection %p\n", utcp->connections[i]);
- buffer_exit(&utcp->connections[i]->rcvbuf);
- buffer_exit(&utcp->connections[i]->sndbuf);
- free(utcp->connections[i]);
+ struct utcp_connection *c = utcp->connections[i];
+ if(!c->reapable)
+ if(c->recv)
+ c->recv(c, NULL, 0);
+ buffer_exit(&c->rcvbuf);
+ buffer_exit(&c->sndbuf);
+ free(c);
}
free(utcp->connections);
free(utcp);
utcp->mtu = mtu;
}
+void utcp_reset_timers(struct utcp *utcp) {
+ if(!utcp)
+ return;
+ struct timeval now, then;
+ gettimeofday(&now, NULL);
+ then = now;
+ then.tv_sec += utcp->timeout;
+ for(int i = 0; i < utcp->nconnections; i++) {
+ utcp->connections[i]->rtrx_timeout = now;
+ utcp->connections[i]->conn_timeout = then;
+ utcp->connections[i]->rtt_start.tv_sec = 0;
+ }
+ if(utcp->rto > START_RTO)
+ utcp->rto = START_RTO;
+}
+
int utcp_get_user_timeout(struct utcp *u) {
return u ? u->timeout : 0;
}
projects / utcp / blobdiff