#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);
}
return NULL;
c->recv = recv;
+ c->priv = priv;
struct hdr hdr;
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);
int32_t cwndleft = c->snd.cwnd - seqdiff(c->snd.nxt, c->snd.una);
char *data = c->sndbuf + seqdiff(c->snd.nxt, c->snd.una);
- fprintf(stderr, "ack, left=%d, cwndleft=%d, sendatleastone=%d\n", left, cwndleft, sendatleastone);
- if(left < 0)
- abort();
+ 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;
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;
// 3. Advance snd.una
uint32_t advanced = seqdiff(hdr.ack, c->snd.una);
- c->snd.una = hdr.ack;
+ uint32_t prevrcvnxt = c->rcv.nxt;
if(advanced) {
- debug("%p advanced %u\n", utcp, advanced);
+ int32_t data_acked = advanced;
+
+ switch(c->state) {
+ case SYN_SENT:
+ case SYN_RECEIVED:
+ data_acked--;
+ break;
+ // TODO: handle FIN as well.
+ default:
+ break;
+ }
+
+ assert(data_acked >= 0);
+
+ int32_t bufused = seqdiff(c->snd.last, c->snd.una);
+ assert(data_acked <= bufused);
+
// Make room in the send buffer.
// TODO: try to avoid memmoving too much. Circular buffer?
- uint32_t left = seqdiff(c->snd.nxt, hdr.ack);
- if(left)
- memmove(c->sndbuf, c->sndbuf + advanced, left);
+ uint32_t left = bufused - data_acked;
+ if(data_acked && left)
+ memmove(c->sndbuf, c->sndbuf + data_acked, left);
+
+ c->snd.una = hdr.ack;
+
c->dupack = 0;
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) {
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)
// FIN counts as one sequence number
c->rcv.nxt++;
+ len++;
// Inform the application that the peer closed the connection.
if(c->recv) {
}
}
- if(!len && !advanced)
- return 0;
-
- if(!len && !(hdr.ctl & SYN) && !(hdr.ctl & FIN))
- return 0;
+ // Now we send something back if:
+ // - we advanced rcv.nxt (ie, we got some data that needs to be ACKed)
+ // -> sendatleastone = true
+ // - or we got an ack, so we should maybe send a bit more data
+ // -> sendatleastone = false
ack:
- ack(c, true);
+ ack(c, prevrcvnxt != c->rcv.nxt);
return 0;
reset:
}
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;
retransmit(c);
}
+ if(c->poll && c->sndbufsize < c->maxsndbufsize / 2)
+ c->poll(c, c->maxsndbufsize - c->sndbufsize);
+
if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <))
next = c->conn_timeout;
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);
}
return c->maxsndbufsize;
}
+size_t utcp_get_sndbuf_free(struct utcp_connection *c) {
+ return c->maxsndbufsize - c->sndbufsize;
+}
+
void utcp_set_sndbuf(struct utcp_connection *c, size_t size) {
c->maxsndbufsize = size;
if(c->maxsndbufsize != size)
size_t utcp_get_outq(struct utcp_connection *c) {
return seqdiff(c->snd.nxt, c->snd.una);
}
+
+void utcp_set_recv_cb(struct utcp_connection *c, utcp_recv_t recv) {
+ c->recv = recv;
+}
+
+void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
+ c->poll = poll;
+}
projects / utcp / blobdiff