#define _GNU_SOURCE
+#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
}
memcpy(&hdr, pkt, sizeof hdr);
- fprintf (stderr, "%p %s: src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
+ fprintf (stderr, "%p %s: len=%zu, src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
if(hdr.ctl & SYN)
debug("SYN");
if(hdr.ctl & RST)
static int compare(const void *va, const void *vb) {
const struct utcp_connection *a = *(struct utcp_connection **)va;
const struct utcp_connection *b = *(struct utcp_connection **)vb;
- if(!a->src || !b->src)
- abort();
+
+ assert(a->src && b->src);
+
int c = (int)a->src - (int)b->src;
if(c)
return c;
static void free_connection(struct utcp_connection *c) {
struct utcp *utcp = c->utcp;
struct utcp_connection **cp = bsearch(&c, utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare);
- if(!cp)
- abort();
+
+ assert(cp);
int i = cp - utcp->connections;
memmove(cp + i, cp + i + 1, (utcp->nconnections - i - 1) * sizeof *cp);
utcp->nconnections--;
+ free(c->sndbuf);
free(c);
}
hdr.dst = c->dst;
hdr.seq = c->snd.iss;
hdr.ack = 0;
- hdr.ctl = SYN;
hdr.wnd = c->rcv.wnd;
+ hdr.ctl = SYN;
+ hdr.aux = 0;
set_state(c, SYN_SENT);
}
static void ack(struct utcp_connection *c, bool sendatleastone) {
- uint32_t left = seqdiff(c->snd.last, c->snd.nxt);
+ int32_t left = seqdiff(c->snd.last, c->snd.nxt);
int32_t cwndleft = c->snd.cwnd - seqdiff(c->snd.nxt, c->snd.una);
char *data = c->sndbuf + seqdiff(c->snd.nxt, c->snd.una);
+ assert(left >= 0);
+
if(cwndleft <= 0)
cwndleft = 0;
pkt.hdr.ack = c->rcv.nxt;
pkt.hdr.wnd = c->snd.wnd;
pkt.hdr.ctl = ACK;
+ pkt.hdr.aux = 0;
do {
uint32_t seglen = left > c->utcp->mtu ? c->utcp->mtu : left;
data += seglen;
left -= seglen;
+ if(c->state != ESTABLISHED && !left && seglen) {
+ switch(c->state) {
+ case FIN_WAIT_1:
+ case CLOSING:
+ seglen--;
+ pkt.hdr.ctl |= FIN;
+ break;
+ default:
+ break;
+ }
+ }
+
print_packet(c->utcp, "send", &pkt, sizeof pkt.hdr + seglen);
c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + seglen);
} while(left);
newbufsize = c->maxsndbufsize;
else
newbufsize = c->sndbufsize * 2;
+ if(bufused + len > newbufsize) {
+ if(bufused + len > c->maxsndbufsize)
+ newbufsize = c->maxsndbufsize;
+ else
+ newbufsize = bufused + len;
+ }
char *newbuf = realloc(c->sndbuf, newbufsize);
if(newbuf) {
c->sndbuf = newbuf;
hdr->dst = tmp;
}
-int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
+ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
if(!utcp) {
errno = EFAULT;
return -1;
c->snd.cwnd += utcp->mtu;
if(c->snd.cwnd > c->maxsndbufsize)
c->snd.cwnd = c->maxsndbufsize;
+ debug("%p increasing cwnd to %u\n", utcp, c->snd.cwnd);
+
+ // Check if we have sent a FIN that is now ACKed.
+ switch(c->state) {
+ case FIN_WAIT_1:
+ if(c->snd.una == c->snd.last)
+ set_state(c, FIN_WAIT_2);
+ break;
+ case CLOSING:
+ if(c->snd.una == c->snd.last) {
+ gettimeofday(&c->conn_timeout, NULL);
+ c->conn_timeout.tv_sec += 60;
+ set_state(c, TIME_WAIT);
+ }
+ break;
+ default:
+ break;
+ }
} else {
if(!len) {
c->dupack++;
if(c->dupack >= 3) {
debug("Triplicate ACK\n");
- abort();
+ //TODO: Resend one packet and go to fast recovery mode. See RFC 6582.
+ //abort();
}
}
}
// 4. Update timers
if(advanced) {
- timerclear(&c->conn_timeout); // It should be set anew in utcp_timeout() if c->snd.una != c->snd.nxt.
+ timerclear(&c->conn_timeout); // It will be set anew in utcp_timeout() if c->snd.una != c->snd.nxt.
if(c->snd.una == c->snd.nxt)
timerclear(&c->rtrx_timeout);
}
abort();
}
- int rxd;
+ ssize_t rxd;
if(c->recv) {
rxd = c->recv(c, data, len);
+ if(rxd != len) {
+ // TODO: once we have a receive buffer, handle the application not accepting all data.
+ fprintf(stderr, "c->recv(%p, %p, %zu) returned %zd\n", c, data, len, rxd);
+ abort();
+ }
if(rxd < 0)
rxd = 0;
else if(rxd > len)
set_state(c, CLOSING);
break;
case FIN_WAIT_2:
+ gettimeofday(&c->conn_timeout, NULL);
+ c->conn_timeout.tv_sec += 60;
set_state(c, TIME_WAIT);
break;
case CLOSE_WAIT:
// FIN counts as one sequence number
c->rcv.nxt++;
+ len++;
// Inform the application that the peer closed the connection.
if(c->recv) {
}
int utcp_shutdown(struct utcp_connection *c, int dir) {
- debug("%p shutdown %d\n", c->utcp, dir);
+ debug("%p shutdown %d\n", c ? c->utcp : NULL, dir);
if(!c) {
errno = EFAULT;
return -1;
return 0;
}
- // Send FIN
-
- struct hdr hdr;
+ c->snd.last++;
- hdr.src = c->src;
- hdr.dst = c->dst;
- hdr.seq = c->snd.nxt;
- hdr.ack = c->rcv.nxt;
- hdr.wnd = c->snd.wnd;
- hdr.ctl = FIN | ACK;
-
- c->snd.nxt += 1;
-
- print_packet(c->utcp, "send", &hdr, sizeof hdr);
- c->utcp->send(c->utcp, &hdr, sizeof hdr);
+ ack(c, false);
return 0;
}
void utcp_exit(struct utcp *utcp) {
if(!utcp)
return;
- for(int i = 0; i < utcp->nconnections; i++)
- free_connection(utcp->connections[i]);
+ for(int i = 0; i < utcp->nconnections; i++) {
+ if(!utcp->connections[i]->reapable)
+ debug("Warning, freeing unclosed connection %p\n", utcp->connections[i]);
+ free(utcp->connections[i]->sndbuf);
+ free(utcp->connections[i]);
+ }
+ free(utcp->connections);
free(utcp);
}