utcp_send_t send;
uint16_t mtu;
+ int timeout;
struct utcp_connection **connections;
int nconnections;
int nallocated;
- int gap;
};
static void set_state(struct utcp_connection *c, enum state state) {
c->state = state;
+ if(state == ESTABLISHED)
+ timerclear(&c->conn_timeout);
fprintf(stderr, "%p new state: %s\n", c->utcp, strstate[state]);
}
-static void print_packet(void *pkt, size_t len) {
+static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, size_t len) {
struct hdr hdr;
if(len < sizeof hdr) {
- fprintf(stderr, "short packet (%zu bytes)\n", len);
+ fprintf(stderr, "%p %s: short packet (%zu bytes)\n", utcp, dir, len);
return;
}
memcpy(&hdr, pkt, sizeof hdr);
- fprintf (stderr, "src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
+ 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);
if(hdr.ctl & SYN)
fprintf(stderr, "SYN");
if(hdr.ctl & RST)
if(len > sizeof hdr) {
fprintf(stderr, " data=");
for(int i = sizeof hdr; i < len; i++) {
- char *data = pkt;
+ const char *data = pkt;
fprintf(stderr, "%c", data[i] >= 32 ? data[i] : '.');
}
}
fprintf(stderr, "\n");
}
-static void list_connections(struct utcp *utcp) {
+static inline void list_connections(struct utcp *utcp) {
fprintf(stderr, "%p has %d connections:\n", utcp, utcp->nconnections);
for(int i = 0; i < utcp->nconnections; i++)
fprintf(stderr, " %u -> %u state %s\n", utcp->connections[i]->src, utcp->connections[i]->dst, strstate[utcp->connections[i]->state]);
static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t src, uint16_t dst) {
// Check whether this combination of src and dst is free
-
+
if(src) {
if(find_connection(utcp, src, dst)) {
errno = EADDRINUSE;
c->snd.nxt = c->snd.iss + 1;
c->rcv.wnd = utcp->mtu;
c->utcp = utcp;
+ c->sndbufsize = 65536;
+ c->sndbuf = malloc(c->sndbufsize);
+ if(!c->sndbuf)
+ c->sndbufsize = 0;
// Add it to the sorted list of connections
set_state(c, SYN_SENT);
+ print_packet(utcp, "send", &hdr, sizeof hdr);
utcp->send(utcp, &hdr, sizeof hdr);
- // Set timeout?
+ gettimeofday(&c->conn_timeout, NULL);
+ c->conn_timeout.tv_sec += utcp->timeout;
return c;
}
set_state(c, ESTABLISHED);
}
-int utcp_send(struct utcp_connection *c, void *data, size_t len) {
+ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
if(c->reapable) {
fprintf(stderr, "Error: send() called on closed connection %p\n", c);
errno = EBADF;
return -1;
}
+ // Add data to send buffer
+
if(!len)
return 0;
return -1;
}
-
+ uint32_t bufused = c->snd.nxt - c->snd.una;
+
+ if(len > c->sndbufsize - bufused)
+ len = c->sndbufsize - bufused;
+
+ memcpy(c->sndbuf + (c->snd.nxt - c->snd.una), data, len);
+
+ // Send segments
+
struct {
struct hdr hdr;
- char data[len];
+ char data[c->utcp->mtu];
} pkt;
pkt.hdr.src = c->src;
pkt.hdr.dst = c->dst;
- pkt.hdr.seq = c->snd.nxt;
pkt.hdr.ack = c->rcv.nxt;
pkt.hdr.wnd = c->snd.wnd;
pkt.hdr.ctl = ACK;
- memcpy(pkt.data, data, len);
+ uint32_t left = len;
- c->snd.nxt += len;
+ while(left) {
+ uint32_t seglen = left > c->utcp->mtu ? c->utcp->mtu : left;
+ pkt.hdr.seq = c->snd.nxt;
- c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + len);
- //
- // Can we add it to the send window?
-
- // Do we need to kick some timers?
-
- return 0;
+ memcpy(pkt.data, data, seglen);
+
+ c->snd.nxt += seglen;
+ data += seglen;
+ left -= seglen;
+
+ print_packet(c->utcp, "send", &pkt, sizeof pkt.hdr + seglen);
+ c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + seglen);
+ }
+
+ fprintf(stderr, "len=%zu\n", len);
+ return len;
}
static void swap_ports(struct hdr *hdr) {
hdr->dst = tmp;
}
-int utcp_recv(struct utcp *utcp, void *data, size_t len) {
+static int32_t seqdiff(uint32_t a, uint32_t b) {
+ return a - b;
+}
+
+int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
if(!utcp) {
errno = EFAULT;
return -1;
return -1;
}
- fprintf(stderr, "%p got: ", utcp);
- print_packet(data, len);
+ print_packet(utcp, "recv", data, len);
struct hdr hdr;
if(len < sizeof hdr) {
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);
return 0;
} else { // CLOSED
}
// It is for an existing connection.
-
+
if(c->state == SYN_SENT) {
if(hdr.ctl & ACK) {
- if(hdr.ack <= c->snd.iss || hdr.ack > c->snd.nxt) {
+ if(seqdiff(hdr.ack, c->snd.iss) <= 0 || seqdiff(hdr.ack, c->snd.nxt) > 0) {
fprintf(stderr, "Invalid ACK, %u %u %u\n", hdr.ack, c->snd.iss, c->snd.nxt);
goto reset;
}
return 0;
set_state(c, CLOSED);
errno = ECONNREFUSED;
- c->recv(c, NULL, 0);
+ if(c->recv)
+ c->recv(c, NULL, 0);
return 0;
}
if(hdr.ctl & SYN) {
if(hdr.ctl & ACK)
c->snd.una = hdr.ack;
- if(c->snd.una > c->snd.iss) {
+ if(seqdiff(c->snd.una, c->snd.iss) > 0) {
set_state(c, ESTABLISHED);
// TODO: signal app?
swap_ports(&hdr);
hdr.ack = c->rcv.nxt;
hdr.ctl = SYN | ACK;
}
+ print_packet(c->utcp, "send", &hdr, sizeof hdr);
utcp->send(utcp, &hdr, sizeof hdr);
// TODO: queue any data?
}
c->snd.wnd = hdr.wnd;
// TODO: check whether segment really starts at rcv.nxt, otherwise trim it.
-
+
if(hdr.ctl & RST) {
switch(c->state) {
case SYN_RECEIVED:
case CLOSE_WAIT:
set_state(c, CLOSED);
errno = ECONNRESET;
- c->recv(c, NULL, 0);
+ if(c->recv)
+ c->recv(c, NULL, 0);
break;
case CLOSING:
case LAST_ACK:
case TIME_WAIT:
set_state(c, CLOSED);
errno = ECONNRESET;
- c->recv(c, NULL, 0);
+ if(c->recv)
+ c->recv(c, NULL, 0);
goto reset;
break;
default:
switch(c->state) {
case SYN_RECEIVED:
- if(hdr.ack >= c->snd.una && hdr.ack <= c->snd.nxt)
+ if(seqdiff(hdr.ack, c->snd.una) >= 0 && seqdiff(hdr.ack, c->snd.nxt) <= 0)
c->utcp->accept(c, hdr.dst);
if(c->state != ESTABLISHED)
goto reset;
+
+ c->snd.una = hdr.ack;
break;
case ESTABLISHED:
case CLOSE_WAIT:
- if(hdr.ack < c->snd.una)
+ if(seqdiff(hdr.ack, c->snd.una) < 0)
return 0;
- if(hdr.ack > c->snd.nxt)
+ if(seqdiff(hdr.ack, c->snd.nxt) > 0)
goto ack_and_drop;
- if(hdr.ack > c->snd.una && hdr.ack <= c->snd.nxt) {
+ if(seqdiff(hdr.ack, c->snd.una) > 0 && seqdiff(hdr.ack, c->snd.nxt) <= 0) {
c->snd.una = hdr.ack;
- if(c->snd.wl1 < hdr.seq || (c->snd.wl1 == hdr.seq && c->snd.wl2 <= hdr.ack)) {
+ if(seqdiff(c->snd.wl1, hdr.seq) < 0 || (c->snd.wl1 == hdr.seq && seqdiff(c->snd.wl2, hdr.ack) <= 0)) {
c->snd.wnd = hdr.wnd;
c->snd.wl1 = hdr.seq;
c->snd.wl2 = hdr.ack;
}
// Process the data
-
+
if(len && c->recv) {
c->recv(c, data, len);
c->rcv.nxt += len;
hdr.seq = 0;
hdr.ctl = RST | ACK;
}
+ print_packet(c->utcp, "send", &hdr, sizeof hdr);
utcp->send(utcp, &hdr, sizeof hdr);
return 0;
hdr.seq = c->snd.nxt;
hdr.ack = c->rcv.nxt;
hdr.ctl = ACK;
+ print_packet(c->utcp, "send", &hdr, sizeof hdr);
utcp->send(utcp, &hdr, sizeof hdr);
if(c->state == CLOSE_WAIT || c->state == TIME_WAIT) {
errno = 0;
- c->recv(c, NULL, 0);
+ if(c->recv)
+ c->recv(c, NULL, 0);
}
return 0;
}
c->snd.nxt += 1;
+ print_packet(c->utcp, "send", &hdr, sizeof hdr);
c->utcp->send(c->utcp, &hdr, sizeof hdr);
return 0;
}
hdr.wnd = 0;
hdr.ctl = RST;
+ print_packet(c->utcp, "send", &hdr, sizeof hdr);
c->utcp->send(c->utcp, &hdr, sizeof hdr);
return 0;
}
-void utcp_timeout(struct utcp *utcp) {
+static void retransmit(struct utcp_connection *c) {
+ if(c->state == CLOSED || c->snd.nxt == c->snd.una)
+ return;
+
+ struct utcp *utcp = c->utcp;
+
+ struct {
+ struct hdr hdr;
+ char data[c->utcp->mtu];
+ } pkt;
+
+ pkt.hdr.src = c->src;
+ pkt.hdr.dst = c->dst;
+
+ switch(c->state) {
+ case LISTEN:
+ // TODO: this should not happen
+ break;
+
+ case SYN_SENT:
+ pkt.hdr.seq = c->snd.iss;
+ pkt.hdr.ack = 0;
+ pkt.hdr.wnd = c->rcv.wnd;
+ pkt.hdr.ctl = SYN;
+ print_packet(c->utcp, "rtrx", &pkt, sizeof pkt.hdr);
+ utcp->send(utcp, &pkt, sizeof pkt.hdr);
+ break;
+
+ case SYN_RECEIVED:
+ pkt.hdr.seq = c->snd.nxt;
+ pkt.hdr.ack = c->rcv.nxt;
+ pkt.hdr.ctl = SYN | ACK;
+ print_packet(c->utcp, "rtrx", &pkt, sizeof pkt.hdr);
+ utcp->send(utcp, &pkt, sizeof pkt.hdr);
+ break;
+
+ case ESTABLISHED:
+ pkt.hdr.seq = c->snd.una;
+ pkt.hdr.ack = c->rcv.nxt;
+ pkt.hdr.ctl = ACK;
+ uint32_t len = seqdiff(c->snd.nxt, c->snd.una);
+ if(len > utcp->mtu)
+ len = utcp->mtu;
+ memcpy(pkt.data, c->sndbuf, len);
+ print_packet(c->utcp, "rtrx", &pkt, sizeof pkt.hdr + len);
+ utcp->send(utcp, &pkt, sizeof pkt.hdr + len);
+ break;
+
+ default:
+ // TODO: implement
+ abort();
+ }
+}
+
+/* Handle timeouts.
+ * One call to this function will loop through all connections,
+ * checking if something needs to be resent or not.
+ * The return value is the time to the next timeout in milliseconds,
+ * or maybe a negative value if the timeout is infinite.
+ */
+int utcp_timeout(struct utcp *utcp) {
struct timeval now;
gettimeofday(&now, NULL);
+ struct timeval next = {now.tv_sec + 3600, now.tv_usec};
for(int i = 0; i < utcp->nconnections; i++) {
struct utcp_connection *c = utcp->connections[i];
if(!c)
continue;
- if(c->reapable) {
- fprintf(stderr, "Reaping %p\n", c);
- free_connection(c);
+ if(c->state == CLOSED) {
+ if(c->reapable) {
+ fprintf(stderr, "Reaping %p\n", c);
+ free_connection(c);
+ i--;
+ }
continue;
}
- if(c->state == CLOSED)
- return;
-
- if(c->conn_timeout.tv_sec && timercmp(&c->conn_timeout, &now, <)) {
- if(!c->reapable) {
- errno = ETIMEDOUT;
- c->recv(c, NULL, 0);
- }
+ if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &now, <)) {
+ errno = ETIMEDOUT;
c->state = CLOSED;
- return;
+ if(c->recv)
+ c->recv(c, NULL, 0);
+ continue;
}
- if(c->rtrx_timeout.tv_sec && timercmp(&c->rtrx_timeout, &now, <)) {
- // TODO: retransmit stuff;
+ if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &now, <)) {
+ retransmit(c);
}
+
+ if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <))
+ next = c->conn_timeout;
+
+ if(c->snd.nxt != c->snd.una) {
+ c->rtrx_timeout = now;
+ c->rtrx_timeout.tv_sec++;
+ } else {
+ timerclear(&c->rtrx_timeout);
+ }
+
+ if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &next, <))
+ next = c->rtrx_timeout;
}
+
+ struct timeval diff;
+ timersub(&next, &now, &diff);
+ if(diff.tv_sec < 0)
+ return 0;
+ return diff.tv_sec * 1000 + diff.tv_usec / 1000;
}
struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv) {
if(!utcp)
return NULL;
+ if(!send) {
+ errno = EFAULT;
+ return NULL;
+ }
+
utcp->accept = accept;
utcp->pre_accept = pre_accept;
utcp->send = send;
utcp->priv = priv;
- utcp->gap = -1;
utcp->mtu = 1000;
+ utcp->timeout = 60;
return utcp;
}
free_connection(utcp->connections[i]);
free(utcp);
}
+
+int utcp_set_connection_timeout(struct utcp *u, int timeout) {
+ int prev = u->timeout;
+ u->timeout = timeout;
+ return prev;
+}
projects / utcp / blobdiff