ssize_t do_recv(struct utcp_connection *c, const void *data, size_t len) {
(void)c;
+
if(!data || !len) {
if(errno) {
debug("Error: %s\n", strerror(errno));
dir &= ~DIR_WRITE;
debug("Connection closed by peer\n");
}
+
return -1;
}
+
if(reference) {
char buf[len];
+
if(fread(buf, len, 1, reference) != 1) {
debug("Error reading reference\n");
abort();
}
+
if(memcmp(buf, data, len)) {
debug("Received data differs from reference\n");
abort();
}
}
+
return write(1, data, len);
}
ssize_t do_send(struct utcp *utcp, const void *data, size_t len) {
int s = *(int *)utcp->priv;
outpktno++;
+
if(outpktno >= dropfrom && outpktno < dropto) {
if(drand48() < dropout) {
debug("Dropped outgoing packet\n");
return len;
}
+
if(!reorder_data && drand48() < reorder) {
reorder_data = malloc(len);
+
if(!reorder_data) {
debug("Out of memory\n");
return len;
}
+
reorder_len = len;
memcpy(reorder_data, data, len);
reorder_countdown = 1 + drand48() * reorder_dist;
total_out += len;
ssize_t result = send(s, data, len, MSG_DONTWAIT);
- if(result <= 0)
+
+ if(result <= 0) {
debug("Error sending UDP packet: %s\n", strerror(errno));
+ }
+
return result;
}
srand(time(NULL));
srand48(time(NULL));
- if(argc < 2 || argc > 3)
+ if(argc < 2 || argc > 3) {
return 1;
+ }
bool server = argc == 2;
bool connected = false;
uint32_t flags = UTCP_TCP;
size_t read_size = 102400;
- if(getenv("DROPIN")) dropin = atof(getenv("DROPIN"));
- if(getenv("DROPOUT")) dropout = atof(getenv("DROPOUT"));
- if(getenv("DROPFROM")) dropfrom = atoi(getenv("DROPFROM"));
- if(getenv("DROPTO")) dropto = atoi(getenv("DROPTO"));
- if(getenv("REORDER")) reorder = atof(getenv("REORDER"));
- if(getenv("REORDER_DIST")) reorder_dist = atoi(getenv("REORDER_DIST"));
- if(getenv("FLAGS")) flags = atoi(getenv("FLAGS"));
- if(getenv("READ_SIZE")) read_size = atoi(getenv("READ_SIZE"));
+ if(getenv("DROPIN")) {
+ dropin = atof(getenv("DROPIN"));
+ }
+
+ if(getenv("DROPOUT")) {
+ dropout = atof(getenv("DROPOUT"));
+ }
+
+ if(getenv("DROPFROM")) {
+ dropfrom = atoi(getenv("DROPFROM"));
+ }
+
+ if(getenv("DROPTO")) {
+ dropto = atoi(getenv("DROPTO"));
+ }
+
+ if(getenv("REORDER")) {
+ reorder = atof(getenv("REORDER"));
+ }
+
+ if(getenv("REORDER_DIST")) {
+ reorder_dist = atoi(getenv("REORDER_DIST"));
+ }
+
+ if(getenv("FLAGS")) {
+ flags = atoi(getenv("FLAGS"));
+ }
+
+ if(getenv("READ_SIZE")) {
+ read_size = atoi(getenv("READ_SIZE"));
+ }
char *reference_filename = getenv("REFERENCE");
- if(reference_filename)
+
+ if(reference_filename) {
reference = fopen(reference_filename, "r");
+ }
- if(dropto < dropfrom)
+ if(dropto < dropfrom) {
dropto = 1 << 30;
+ }
struct addrinfo *ai;
+
struct addrinfo hint = {
.ai_flags = server ? AI_PASSIVE : 0,
.ai_socktype = SOCK_DGRAM,
};
getaddrinfo(server ? NULL : argv[1], server ? argv[1] : argv[2], &hint, &ai);
- if(!ai)
+
+ if(!ai) {
return 1;
+ }
int s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
- if(s == -1)
+
+ if(s == -1) {
return 1;
+ }
if(server) {
- if(bind(s, ai->ai_addr, ai->ai_addrlen))
+ if(bind(s, ai->ai_addr, ai->ai_addrlen)) {
return 1;
+ }
} else {
- if(connect(s, ai->ai_addr, ai->ai_addrlen))
+ if(connect(s, ai->ai_addr, ai->ai_addrlen)) {
return 1;
+ }
+
connected = true;
}
freeaddrinfo(ai);
struct utcp *u = utcp_init(server ? do_accept : NULL, NULL, do_send, &s);
- if(!u)
+
+ if(!u) {
return 1;
+ }
utcp_set_mtu(u, 1300);
utcp_set_user_timeout(u, 10);
- if(!server)
+ if(!server) {
c = utcp_connect_ex(u, 1, do_recv, NULL, flags);
+ }
struct pollfd fds[2] = {
{.fd = 0, .events = POLLIN | POLLERR | POLLHUP},
};
char buf[102400];
+
struct timeval timeout = utcp_timeout(u);
while(!connected || utcp_is_active(u)) {
size_t max = c ? utcp_get_sndbuf_free(c) : 0;
- if(max > sizeof(buf))
+
+ if(max > sizeof(buf)) {
max = sizeof(buf);
- if(max > read_size)
+ }
+
+ if(max > read_size) {
max = read_size;
+ }
int timeout_ms = timeout.tv_sec * 1000 + timeout.tv_usec / 1000 + 1;
debug("polling, dir = %d, timeout = %d\n", dir, timeout_ms);
- if((dir & DIR_READ) && max)
+
+ if((dir & DIR_READ) && max) {
poll(fds, 2, timeout_ms);
- else
+ } else {
poll(fds + 1, 1, timeout_ms);
+ }
if(fds[0].revents) {
fds[0].revents = 0;
debug("stdin\n");
ssize_t len = read(0, buf, max);
+
if(len <= 0) {
fds[0].fd = -1;
dir &= ~DIR_READ;
- if(c)
+
+ if(c) {
utcp_shutdown(c, SHUT_WR);
- if(len == -1)
+ }
+
+ if(len == -1) {
break;
- else
+ } else {
continue;
+ }
}
+
if(c) {
ssize_t sent = utcp_send(c, buf, len);
- if(sent != len)
+
+ if(sent != len) {
debug("Short send: %zd != %zd\n", sent, len);
+ }
}
}
struct sockaddr_storage ss;
socklen_t sl = sizeof(ss);
int len = recvfrom(s, buf, sizeof(buf), MSG_DONTWAIT, (struct sockaddr *)&ss, &sl);
+
if(len <= 0) {
debug("Error receiving UDP packet: %s\n", strerror(errno));
break;
}
+
if(!connected)
- if(!connect(s, (struct sockaddr *)&ss, sl))
+ if(!connect(s, (struct sockaddr *)&ss, sl)) {
connected = true;
+ }
+
inpktno++;
+
if(inpktno >= dropto || inpktno < dropfrom || drand48() >= dropin) {
total_in += len;
- if(utcp_recv(u, buf, len) == -1)
+
+ if(utcp_recv(u, buf, len) == -1) {
debug("Error receiving UTCP packet: %s\n", strerror(errno));
+ }
} else {
debug("Dropped incoming packet\n");
}
};
utcp_close(c);
+
utcp_exit(u);
+
free(reorder_data);
debug("Total bytes in: %ld, out: %ld\n", total_in, total_out);
#endif
#ifndef timersub
-#define timersub(a, b, r) do {\
- (r)->tv_sec = (a)->tv_sec - (b)->tv_sec;\
- (r)->tv_usec = (a)->tv_usec - (b)->tv_usec;\
- if((r)->tv_usec < 0)\
- (r)->tv_sec--, (r)->tv_usec += USEC_PER_SEC;\
-} while (0)
+#define timersub(a, b, r)\
+ do {\
+ (r)->tv_sec = (a)->tv_sec - (b)->tv_sec;\
+ (r)->tv_usec = (a)->tv_usec - (b)->tv_usec;\
+ if((r)->tv_usec < 0)\
+ (r)->tv_sec--, (r)->tv_usec += USEC_PER_SEC;\
+ } while (0)
#endif
static inline size_t max(size_t a, size_t b) {
static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, size_t len) {
struct hdr hdr;
+
if(len < sizeof(hdr)) {
debug("%p %s: short packet (%lu bytes)\n", utcp, dir, (unsigned long)len);
return;
memcpy(&hdr, pkt, sizeof(hdr));
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)
+
+ if(hdr.ctl & SYN) {
debug("SYN");
- if(hdr.ctl & RST)
+ }
+
+ if(hdr.ctl & RST) {
debug("RST");
- if(hdr.ctl & FIN)
+ }
+
+ if(hdr.ctl & FIN) {
debug("FIN");
- if(hdr.ctl & ACK)
+ }
+
+ if(hdr.ctl & ACK) {
debug("ACK");
+ }
if(len > sizeof(hdr)) {
uint32_t datalen = len - sizeof(hdr);
*p++ = "0123456789ABCDEF"[data[i] >> 4];
*p++ = "0123456789ABCDEF"[data[i] & 15];
}
+
*p = 0;
debug(" data=%s", str);
static void set_state(struct utcp_connection *c, enum state state) {
c->state = state;
- if(state == ESTABLISHED)
+
+ if(state == ESTABLISHED) {
timerclear(&c->conn_timeout);
+ }
+
debug("%p new state: %s\n", c->utcp, strstate[state]);
}
static bool fin_wanted(struct utcp_connection *c, uint32_t seq) {
- if(seq != c->snd.last)
+ if(seq != c->snd.last) {
return false;
+ }
+
switch(c->state) {
case FIN_WAIT_1:
case CLOSING:
case LAST_ACK:
return true;
+
default:
return false;
}
debug("buffer_put_at %lu %lu %lu\n", (unsigned long)buf->used, (unsigned long)offset, (unsigned long)len);
size_t required = offset + len;
+
if(required > buf->maxsize) {
- if(offset >= buf->maxsize)
+ if(offset >= buf->maxsize) {
return 0;
+ }
+
len = buf->maxsize - offset;
required = buf->maxsize;
}
if(required > buf->size) {
size_t newsize = buf->size;
+
if(!newsize) {
newsize = required;
} else {
newsize *= 2;
} while(newsize < required);
}
- if(newsize > buf->maxsize)
+
+ if(newsize > buf->maxsize) {
newsize = buf->maxsize;
+ }
+
char *newdata = realloc(buf->data, newsize);
- if(!newdata)
+
+ if(!newdata) {
return -1;
+ }
+
buf->data = newdata;
buf->size = newsize;
}
memcpy(buf->data + offset, data, len);
- if(required > buf->used)
+
+ if(required > buf->used) {
buf->used = required;
+ }
+
return len;
}
// Get data from the buffer. data can be NULL.
static ssize_t buffer_get(struct buffer *buf, void *data, size_t len) {
- if(len > buf->used)
+ if(len > buf->used) {
len = buf->used;
- if(data)
+ }
+
+ if(data) {
memcpy(data, buf->data, len);
- if(len < buf->used)
+ }
+
+ if(len < buf->used) {
memmove(buf->data, buf->data + len, buf->used - len);
+ }
+
buf->used -= len;
return len;
}
// Copy data from the buffer without removing it.
static ssize_t buffer_copy(struct buffer *buf, void *data, size_t offset, size_t len) {
- if(offset >= buf->used)
+ if(offset >= buf->used) {
return 0;
- if(offset + len > buf->used)
+ }
+
+ if(offset + len > buf->used) {
len = buf->used - offset;
+ }
+
memcpy(data, buf->data + offset, len);
return len;
}
static bool buffer_init(struct buffer *buf, uint32_t len, uint32_t maxlen) {
memset(buf, 0, sizeof(*buf));
+
if(len) {
buf->data = malloc(len);
- if(!buf->data)
+
+ if(!buf->data) {
return false;
+ }
}
+
buf->size = len;
buf->maxsize = maxlen;
return true;
assert(a->src && b->src);
int c = (int)a->src - (int)b->src;
- if(c)
+
+ if(c) {
return c;
+ }
+
c = (int)a->dst - (int)b->dst;
return c;
}
static struct utcp_connection *find_connection(const struct utcp *utcp, uint16_t src, uint16_t dst) {
- if(!utcp->nconnections)
+ if(!utcp->nconnections) {
return NULL;
+ }
+
struct utcp_connection key = {
.src = src,
.dst = dst,
errno = ENOMEM;
return NULL;
}
+
src = rand() | 0x8000;
- while(find_connection(utcp, src, dst))
+
+ while(find_connection(utcp, src, dst)) {
src++;
+ }
}
// Allocate memory for the new connection
if(utcp->nconnections >= utcp->nallocated) {
- if(!utcp->nallocated)
+ if(!utcp->nallocated) {
utcp->nallocated = 4;
- else
+ } else {
utcp->nallocated *= 2;
+ }
+
struct utcp_connection **new_array = realloc(utcp->connections, utcp->nallocated * sizeof(*utcp->connections));
- if(!new_array)
+
+ if(!new_array) {
return NULL;
+ }
+
utcp->connections = new_array;
}
struct utcp_connection *c = calloc(1, sizeof(*c));
- if(!c)
+
+ if(!c) {
return NULL;
+ }
if(!buffer_init(&c->sndbuf, DEFAULT_SNDBUFSIZE, DEFAULT_MAXSNDBUFSIZE)) {
free(c);
}
static inline uint32_t absdiff(uint32_t a, uint32_t b) {
- if(a > b)
+ if(a > b) {
return a - b;
- else
+ } else {
return b - a;
+ }
}
// Update RTT variables. See RFC 6298.
utcp->rto = utcp->srtt + max(utcp->rttvar, CLOCK_GRANULARITY);
}
- if(utcp->rto > MAX_RTO)
+ if(utcp->rto > MAX_RTO) {
utcp->rto = MAX_RTO;
+ }
debug("rtt %u srtt %u rttvar %u rto %u\n", rtt, utcp->srtt, utcp->rttvar, utcp->rto);
}
static void start_retransmit_timer(struct utcp_connection *c) {
gettimeofday(&c->rtrx_timeout, NULL);
c->rtrx_timeout.tv_usec += c->utcp->rto;
+
while(c->rtrx_timeout.tv_usec >= 1000000) {
c->rtrx_timeout.tv_usec -= 1000000;
c->rtrx_timeout.tv_sec++;
}
+
debug("timeout set to %lu.%06lu (%u)\n", c->rtrx_timeout.tv_sec, c->rtrx_timeout.tv_usec, c->utcp->rto);
}
struct utcp_connection *utcp_connect_ex(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv, uint32_t flags) {
struct utcp_connection *c = allocate_connection(utcp, 0, dst);
- if(!c)
+
+ if(!c) {
return NULL;
+ }
assert((flags & ~0xf) == 0);
assert(left >= 0);
- if(cwndleft <= 0)
+ if(cwndleft <= 0) {
cwndleft = 0;
+ }
- if(cwndleft < left)
+ if(cwndleft < left) {
left = cwndleft;
+ }
- if(!left && !sendatleastone)
+ if(!left && !sendatleastone) {
return;
+ }
struct {
struct hdr hdr;
} *pkt;
pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu);
- if(!pkt)
+
+ if(!pkt) {
return;
+ }
pkt->hdr.src = c->src;
pkt->hdr.dst = c->dst;
debug("Error: send() called on unconnected connection %p\n", c);
errno = ENOTCONN;
return -1;
+
case ESTABLISHED:
case CLOSE_WAIT:
break;
+
case FIN_WAIT_1:
case FIN_WAIT_2:
case CLOSING:
// Exit early if we have nothing to send.
- if(!len)
+ if(!len) {
return 0;
+ }
if(!data) {
errno = EFAULT;
// Add data to send buffer.
len = buffer_put(&c->sndbuf, data, len);
+
if(len <= 0) {
errno = EWOULDBLOCK;
return 0;
c->snd.last += len;
ack(c, false);
+
if(!is_reliable(c)) {
c->snd.una = c->snd.nxt = c->snd.last;
buffer_get(&c->sndbuf, NULL, c->sndbuf.used);
}
- if(is_reliable(c) && !timerisset(&c->rtrx_timeout))
+
+ if(is_reliable(c) && !timerisset(&c->rtrx_timeout)) {
start_retransmit_timer(c);
+ }
+
return len;
}
} *pkt;
pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu);
- if(!pkt)
+
+ if(!pkt) {
return;
+ }
pkt->hdr.src = c->src;
pkt->hdr.dst = c->dst;
pkt->hdr.aux = 0;
switch(c->state) {
- case SYN_SENT:
- // Send our SYN again
- pkt->hdr.seq = c->snd.iss;
- pkt->hdr.ack = 0;
- pkt->hdr.ctl = SYN;
- 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_SENT:
+ // Send our SYN again
+ pkt->hdr.seq = c->snd.iss;
+ pkt->hdr.ack = 0;
+ pkt->hdr.ctl = SYN;
+ 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:
- // Send SYNACK again
- 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 SYN_RECEIVED:
+ // Send SYNACK again
+ 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:
- case FIN_WAIT_1:
- case CLOSE_WAIT:
- case CLOSING:
- case LAST_ACK:
- // Send unacked data again.
- pkt->hdr.seq = c->snd.una;
- pkt->hdr.ack = c->rcv.nxt;
- pkt->hdr.ctl = ACK;
- uint32_t len = seqdiff(c->snd.last, c->snd.una);
- if(len > utcp->mtu)
- len = utcp->mtu;
- if(fin_wanted(c, c->snd.una + len)) {
- len--;
- pkt->hdr.ctl |= FIN;
- }
- c->snd.nxt = c->snd.una + len;
- c->snd.cwnd = utcp->mtu; // reduce cwnd on retransmit
- buffer_copy(&c->sndbuf, pkt->data, 0, len);
- print_packet(c->utcp, "rtrx", pkt, sizeof(pkt->hdr) + len);
- utcp->send(utcp, pkt, sizeof(pkt->hdr) + len);
- break;
+ case ESTABLISHED:
+ case FIN_WAIT_1:
+ case CLOSE_WAIT:
+ case CLOSING:
+ case LAST_ACK:
+ // Send unacked data again.
+ pkt->hdr.seq = c->snd.una;
+ pkt->hdr.ack = c->rcv.nxt;
+ pkt->hdr.ctl = ACK;
+ uint32_t len = seqdiff(c->snd.last, c->snd.una);
+
+ if(len > utcp->mtu) {
+ len = utcp->mtu;
+ }
- case CLOSED:
- case LISTEN:
- case TIME_WAIT:
- case FIN_WAIT_2:
- // We shouldn't need to retransmit anything in this state.
+ if(fin_wanted(c, c->snd.una + len)) {
+ len--;
+ pkt->hdr.ctl |= FIN;
+ }
+
+ c->snd.nxt = c->snd.una + len;
+ c->snd.cwnd = utcp->mtu; // reduce cwnd on retransmit
+ buffer_copy(&c->sndbuf, pkt->data, 0, len);
+ print_packet(c->utcp, "rtrx", pkt, sizeof(pkt->hdr) + len);
+ utcp->send(utcp, pkt, sizeof(pkt->hdr) + len);
+ break;
+
+ case CLOSED:
+ case LISTEN:
+ case TIME_WAIT:
+ case FIN_WAIT_2:
+ // We shouldn't need to retransmit anything in this state.
#ifdef UTCP_DEBUG
- abort();
+ abort();
#endif
- stop_retransmit_timer(c);
- goto cleanup;
+ stop_retransmit_timer(c);
+ goto cleanup;
}
start_retransmit_timer(c);
utcp->rto *= 2;
- if(utcp->rto > MAX_RTO)
+
+ if(utcp->rto > MAX_RTO) {
utcp->rto = MAX_RTO;
+ }
+
c->rtt_start.tv_sec = 0; // invalidate RTT timer
cleanup:
*/
static void sack_consume(struct utcp_connection *c, size_t len) {
debug("sack_consume %lu\n", (unsigned long)len);
+
if(len > c->rcvbuf.used) {
debug("All SACK entries consumed");
c->sacks[0].len = 0;
buffer_get(&c->rcvbuf, NULL, len);
- for(int i = 0; i < NSACKS && c->sacks[i].len; ) {
+ for(int i = 0; i < NSACKS && c->sacks[i].len;) {
if(len < c->sacks[i].offset) {
c->sacks[i].offset -= len;
i++;
}
}
- for(int i = 0; i < NSACKS && c->sacks[i].len; i++)
+ for(int i = 0; i < NSACKS && c->sacks[i].len; i++) {
debug("SACK[%d] offset %u len %u\n", i, c->sacks[i].offset, c->sacks[i].len);
+ }
}
static void handle_out_of_order(struct utcp_connection *c, uint32_t offset, const void *data, size_t len) {
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 < 0 || (size_t)rxd < len)
+
+ if(rxd < 0 || (size_t)rxd < len) {
abort();
+ }
// Make note of where we put it.
for(int i = 0; i < NSACKS; i++) {
} else {
debug("SACK entries full, dropping packet\n");
}
+
break;
} else { // merge
debug("Merge with start of SACK entry at %d\n", i);
c->sacks[i].len = offset + rxd - c->sacks[i].offset;
// TODO: handle potential merge with next entry
}
+
break;
}
}
- for(int i = 0; i < NSACKS && c->sacks[i].len; i++)
+ for(int i = 0; i < NSACKS && c->sacks[i].len; i++) {
debug("SACK[%d] offset %u len %u\n", i, c->sacks[i].offset, c->sacks[i].len);
+ }
}
static void handle_in_order(struct utcp_connection *c, const void *data, size_t len) {
if(c->recv) {
ssize_t rxd = c->recv(c, data, len);
+
if(rxd < 0 || (size_t)rxd != len) {
// TODO: handle the application not accepting all data.
abort();
}
}
- if(c->rcvbuf.used)
+ if(c->rcvbuf.used) {
sack_consume(c, len);
+ }
c->rcv.nxt += len;
}
}
uint32_t offset = seqdiff(seq, c->rcv.nxt);
- if(offset + len > c->rcvbuf.maxsize)
+
+ if(offset + len > c->rcvbuf.maxsize) {
abort();
+ }
- if(offset)
+ if(offset) {
handle_out_of_order(c, offset, data, len);
- else
+ } else {
handle_in_order(c, data, len);
+ }
}
return -1;
}
- if(!len)
+ if(!len) {
return 0;
+ }
if(!data) {
errno = EFAULT;
// Drop packets smaller than the header
struct hdr hdr;
+
if(len < sizeof(hdr)) {
errno = EBADMSG;
return -1;
const uint8_t *init = NULL;
uint16_t aux = hdr.aux;
+
while(aux) {
size_t auxlen = 4 * (aux >> 8) & 0xf;
uint8_t auxtype = aux & 0xff;
errno = EBADMSG;
return -1;
}
+
init = data;
break;
+
default:
errno = EBADMSG;
return -1;
len -= auxlen;
data += auxlen;
- if(!(aux & 0x800))
+ if(!(aux & 0x800)) {
break;
+ }
if(len < 2) {
errno = EBADMSG;
if(!c) {
// Ignore RST packets
- if(hdr.ctl & RST)
+ if(hdr.ctl & RST) {
return 0;
+ }
// Is it a SYN packet and are we LISTENing?
// Try to allocate memory, otherwise send a RST back
c = allocate_connection(utcp, hdr.dst, hdr.src);
+
if(!c) {
len = 1;
goto reset;
len = 1;
goto reset;
}
+
c->flags = init[3] & 0x7;
} else {
c->flags = UTCP_TCP;
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;
case LAST_ACK:
case TIME_WAIT:
break;
+
default:
#ifdef UTCP_DEBUG
abort();
bool acceptable;
- if(c->state == SYN_SENT)
+ if(c->state == SYN_SENT) {
acceptable = true;
- else if(len == 0)
+ } else if(len == 0) {
acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0;
- else {
+ } else {
int32_t rcv_offset = seqdiff(hdr.seq, c->rcv.nxt);
// cut already accepted front overlapping
if(rcv_offset < 0) {
- acceptable = len > (size_t)-rcv_offset;
+ acceptable = len > (size_t) - rcv_offset;
+
if(acceptable) {
data -= rcv_offset;
len += rcv_offset;
if(!acceptable) {
debug("Packet not acceptable, %u <= %u + %lu < %u\n", c->rcv.nxt, hdr.seq, (unsigned long)len, c->rcv.nxt + c->rcvbuf.maxsize);
+
// Ignore unacceptable RST packets.
- if(hdr.ctl & RST)
+ if(hdr.ctl & RST) {
return 0;
+ }
+
// Otherwise, continue processing.
len = 0;
}
if(hdr.ctl & ACK && (seqdiff(hdr.ack, c->snd.last) > 0 || seqdiff(hdr.ack, c->snd.una) < 0)) {
debug("Packet ack seqno out of range, %u <= %u < %u\n", c->snd.una, hdr.ack, c->snd.una + c->sndbuf.used);
+
// Ignore unacceptable RST packets.
- if(hdr.ctl & RST)
+ if(hdr.ctl & RST) {
return 0;
+ }
+
goto reset;
}
if(hdr.ctl & RST) {
switch(c->state) {
case SYN_SENT:
- if(!(hdr.ctl & ACK))
+ if(!(hdr.ctl & ACK)) {
return 0;
+ }
+
// The peer has refused our connection.
set_state(c, CLOSED);
errno = ECONNREFUSED;
- if(c->recv)
+
+ if(c->recv) {
c->recv(c, NULL, 0);
+ }
+
return 0;
+
case SYN_RECEIVED:
- if(hdr.ctl & ACK)
+ if(hdr.ctl & ACK) {
return 0;
+ }
+
// We haven't told the application about this connection yet. Silently delete.
free_connection(c);
return 0;
+
case ESTABLISHED:
case FIN_WAIT_1:
case FIN_WAIT_2:
case CLOSE_WAIT:
- if(hdr.ctl & ACK)
+ if(hdr.ctl & ACK) {
return 0;
+ }
+
// The peer has aborted our connection.
set_state(c, CLOSED);
errno = ECONNRESET;
- if(c->recv)
+
+ if(c->recv) {
c->recv(c, NULL, 0);
+ }
+
return 0;
+
case CLOSING:
case LAST_ACK:
case TIME_WAIT:
- if(hdr.ctl & ACK)
+ if(hdr.ctl & ACK) {
return 0;
+ }
+
// As far as the application is concerned, the connection has already been closed.
// If it has called utcp_close() already, we can immediately free this connection.
if(c->reapable) {
free_connection(c);
return 0;
}
+
// Otherwise, immediately move to the CLOSED state.
set_state(c, CLOSED);
return 0;
+
default:
#ifdef UTCP_DEBUG
abort();
}
}
- if(!(hdr.ctl & ACK))
+ if(!(hdr.ctl & ACK)) {
goto skip_ack;
+ }
// 3. Advance snd.una
int32_t data_acked = advanced;
switch(c->state) {
- case SYN_SENT:
- case SYN_RECEIVED:
- data_acked--;
- break;
- // TODO: handle FIN as well.
- default:
- break;
+ 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);
- if(data_acked)
+ if(data_acked) {
buffer_get(&c->sndbuf, NULL, data_acked);
+ }
// Also advance snd.nxt if possible
- if(seqdiff(c->snd.nxt, hdr.ack) < 0)
+ if(seqdiff(c->snd.nxt, hdr.ack) < 0) {
c->snd.nxt = hdr.ack;
+ }
c->snd.una = hdr.ack;
c->dupack = 0;
c->snd.cwnd += utcp->mtu;
- if(c->snd.cwnd > c->sndbuf.maxsize)
+
+ if(c->snd.cwnd > c->sndbuf.maxsize) {
c->snd.cwnd = c->sndbuf.maxsize;
+ }
// 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)
+ 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 && is_reliable(c)) {
c->dupack++;
+
if(c->dupack == 3) {
debug("Triplicate ACK\n");
//TODO: Resend one packet and go to fast recovery mode. See RFC 6582.
if(advanced) {
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.last)
+
+ if(c->snd.una == c->snd.last) {
stop_retransmit_timer(c);
- else if(is_reliable(c))
+ } else if(is_reliable(c)) {
start_retransmit_timer(c);
+ }
}
skip_ack:
if(hdr.ctl & SYN) {
switch(c->state) {
case SYN_SENT:
+
// This is a SYNACK. It should always have ACKed the SYN.
- if(!advanced)
+ if(!advanced) {
goto reset;
+ }
+
c->rcv.irs = hdr.seq;
c->rcv.nxt = hdr.seq;
set_state(c, ESTABLISHED);
// TODO: notify application of this somehow.
break;
+
case SYN_RECEIVED:
case ESTABLISHED:
case FIN_WAIT_1:
case TIME_WAIT:
// Ehm, no. We should never receive a second SYN.
return 0;
+
default:
#ifdef UTCP_DEBUG
abort();
if(c->state == SYN_RECEIVED) {
// This is the ACK after the SYNACK. It should always have ACKed the SYNACK.
- if(!advanced)
+ if(!advanced) {
goto reset;
+ }
// Are we still LISTENing?
- if(utcp->accept)
+ if(utcp->accept) {
utcp->accept(c, c->src);
+ }
if(c->state != ESTABLISHED) {
set_state(c, CLOSED);
abort();
#endif
return 0;
+
case ESTABLISHED:
case FIN_WAIT_1:
case FIN_WAIT_2:
break;
+
case CLOSE_WAIT:
case CLOSING:
case LAST_ACK:
case TIME_WAIT:
// Ehm no, We should never receive more data after a FIN.
goto reset;
+
default:
#ifdef UTCP_DEBUG
abort();
abort();
#endif
break;
+
case ESTABLISHED:
set_state(c, CLOSE_WAIT);
break;
+
case FIN_WAIT_1:
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:
case CLOSING:
case LAST_ACK:
case TIME_WAIT:
// Ehm, no. We should never receive a second FIN.
goto reset;
+
default:
#ifdef UTCP_DEBUG
abort();
swap_ports(&hdr);
hdr.wnd = 0;
hdr.aux = 0;
+
if(hdr.ctl & ACK) {
hdr.seq = hdr.ack;
hdr.ctl = RST;
hdr.seq = 0;
hdr.ctl = RST | ACK;
}
+
print_packet(utcp, "send", &hdr, sizeof(hdr));
utcp->send(utcp, &hdr, sizeof(hdr));
return 0;
int utcp_shutdown(struct utcp_connection *c, int dir) {
debug("%p shutdown %d at %u\n", c ? c->utcp : NULL, dir, c ? c->snd.last : 0);
+
if(!c) {
errno = EFAULT;
return -1;
// TCP does not have a provision for stopping incoming packets.
// The best we can do is to just ignore them.
- if(dir == UTCP_SHUT_RD || dir == UTCP_SHUT_RDWR)
+ if(dir == UTCP_SHUT_RD || dir == UTCP_SHUT_RDWR) {
c->recv = NULL;
+ }
// The rest of the code deals with shutting down writes.
- if(dir == UTCP_SHUT_RD)
+ if(dir == UTCP_SHUT_RD) {
return 0;
+ }
switch(c->state) {
case CLOSED:
case ESTABLISHED:
set_state(c, FIN_WAIT_1);
break;
+
case FIN_WAIT_1:
case FIN_WAIT_2:
return 0;
+
case CLOSE_WAIT:
set_state(c, CLOSING);
break;
c->snd.last++;
ack(c, false);
- if(!timerisset(&c->rtrx_timeout))
+
+ if(!timerisset(&c->rtrx_timeout)) {
start_retransmit_timer(c);
+ }
+
return 0;
}
int utcp_close(struct utcp_connection *c) {
- if(utcp_shutdown(c, SHUT_RDWR) && errno != ENOTCONN)
+ if(utcp_shutdown(c, SHUT_RDWR) && errno != ENOTCONN) {
return -1;
+ }
+
c->recv = NULL;
c->poll = NULL;
c->reapable = true;
switch(c->state) {
case CLOSED:
return 0;
+
case LISTEN:
case SYN_SENT:
case CLOSING:
for(int i = 0; i < utcp->nconnections; i++) {
struct utcp_connection *c = utcp->connections[i];
- if(!c)
+
+ if(!c) {
continue;
+ }
// delete connections that have been utcp_close()d.
if(c->state == CLOSED) {
free_connection(c);
i--;
}
+
continue;
}
if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &now, <)) {
errno = ETIMEDOUT;
c->state = CLOSED;
- if(c->recv)
+
+ if(c->recv) {
c->recv(c, NULL, 0);
+ }
+
continue;
}
if(c->poll) {
if((c->state == ESTABLISHED || c->state == CLOSE_WAIT)) {
uint32_t len = buffer_free(&c->sndbuf);
- if(len)
+
+ if(len) {
c->poll(c, len);
+ }
} else if(c->state == CLOSED) {
c->poll(c, 0);
}
}
- if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <))
+ if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <)) {
next = c->conn_timeout;
+ }
- if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &next, <))
+ if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &next, <)) {
next = c->rtrx_timeout;
+ }
}
struct timeval diff;
+
timersub(&next, &now, &diff);
+
return diff;
}
bool utcp_is_active(struct utcp *utcp) {
- if(!utcp)
+ if(!utcp) {
return false;
+ }
for(int i = 0; i < utcp->nconnections; i++)
- if(utcp->connections[i]->state != CLOSED && utcp->connections[i]->state != TIME_WAIT)
+ if(utcp->connections[i]->state != CLOSED && utcp->connections[i]->state != TIME_WAIT) {
return true;
+ }
return false;
}
}
struct utcp *utcp = calloc(1, sizeof(*utcp));
- if(!utcp)
+
+ if(!utcp) {
return NULL;
+ }
utcp->accept = accept;
utcp->pre_accept = pre_accept;
}
void utcp_exit(struct utcp *utcp) {
- if(!utcp)
+ if(!utcp) {
return;
+ }
+
for(int i = 0; i < utcp->nconnections; i++) {
struct utcp_connection *c = utcp->connections[i];
+
if(!c->reapable)
- if(c->recv)
+ if(c->recv) {
c->recv(c, NULL, 0);
+ }
+
buffer_exit(&c->rcvbuf);
buffer_exit(&c->sndbuf);
free(c);
}
+
free(utcp->connections);
free(utcp);
}
void utcp_set_mtu(struct utcp *utcp, uint16_t mtu) {
// TODO: handle overhead of the header
- if(utcp)
+ if(utcp) {
utcp->mtu = mtu;
+ }
}
void utcp_reset_timers(struct utcp *utcp) {
- if(!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)
+
+ if(utcp->rto > START_RTO) {
utcp->rto = START_RTO;
+ }
}
int utcp_get_user_timeout(struct utcp *u) {
}
void utcp_set_user_timeout(struct utcp *u, int timeout) {
- if(u)
+ if(u) {
u->timeout = timeout;
+ }
}
size_t utcp_get_sndbuf(struct utcp_connection *c) {
}
size_t utcp_get_sndbuf_free(struct utcp_connection *c) {
- if(c && (c->state == ESTABLISHED || c->state == CLOSE_WAIT))
+ if(c && (c->state == ESTABLISHED || c->state == CLOSE_WAIT)) {
return buffer_free(&c->sndbuf);
- else
+ } else {
return 0;
+ }
}
void utcp_set_sndbuf(struct utcp_connection *c, size_t size) {
- if(!c)
+ if(!c) {
return;
+ }
+
c->sndbuf.maxsize = size;
- if(c->sndbuf.maxsize != size)
+
+ if(c->sndbuf.maxsize != size) {
c->sndbuf.maxsize = -1;
+ }
}
size_t utcp_get_rcvbuf(struct utcp_connection *c) {
}
size_t utcp_get_rcvbuf_free(struct utcp_connection *c) {
- if(c && (c->state == ESTABLISHED || c->state == CLOSE_WAIT))
+ if(c && (c->state == ESTABLISHED || c->state == CLOSE_WAIT)) {
return buffer_free(&c->rcvbuf);
- else
+ } else {
return 0;
+ }
}
void utcp_set_rcvbuf(struct utcp_connection *c, size_t size) {
- if(!c)
+ if(!c) {
return;
+ }
+
c->rcvbuf.maxsize = size;
- if(c->rcvbuf.maxsize != size)
+
+ if(c->rcvbuf.maxsize != size) {
c->rcvbuf.maxsize = -1;
+ }
}
bool utcp_get_nodelay(struct utcp_connection *c) {
}
void utcp_set_nodelay(struct utcp_connection *c, bool nodelay) {
- if(c)
+ if(c) {
c->nodelay = nodelay;
+ }
}
bool utcp_get_keepalive(struct utcp_connection *c) {
}
void utcp_set_keepalive(struct utcp_connection *c, bool keepalive) {
- if(c)
+ if(c) {
c->keepalive = keepalive;
+ }
}
size_t utcp_get_outq(struct utcp_connection *c) {
}
void utcp_set_recv_cb(struct utcp_connection *c, utcp_recv_t recv) {
- if(c)
+ if(c) {
c->recv = recv;
+ }
}
void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
- if(c)
+ if(c) {
c->poll = poll;
+ }
}
void utcp_set_accept_cb(struct utcp *utcp, utcp_accept_t accept, utcp_pre_accept_t pre_accept) {
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