From: Guus Sliepen Date: Mon, 2 Oct 2017 20:52:53 +0000 (+0200) Subject: Format the code using the Artistic Style formatter. X-Git-Url: https://git.meshlink.io/?a=commitdiff_plain;h=850542e9585f716985c25d5995ba5bcb2cc6ba87;p=utcp Format the code using the Artistic Style formatter. --- diff --git a/.astylerc b/.astylerc new file mode 100644 index 0000000..ba38946 --- /dev/null +++ b/.astylerc @@ -0,0 +1,10 @@ +--indent=tab=8 +--convert-tabs +-j +-f +-A2 +-U +-p +-xg +-k3 +-w diff --git a/.gitignore b/.gitignore index 4b29b74..980671a 100644 --- a/.gitignore +++ b/.gitignore @@ -1,4 +1,6 @@ .* +!.astylerc +!.gitignore *~ *.o /test diff --git a/Makefile b/Makefile index c2429e5..9748954 100644 --- a/Makefile +++ b/Makefile @@ -14,4 +14,7 @@ selftest: utcp.o selftest.c clean: rm -f *.o $(BIN) -.PHONY: clean +astyle: + astyle --options=.astylerc -nQ *.c *.h + +.PHONY: clean astyle diff --git a/selftest.c b/selftest.c index da6b7ca..0b8a891 100644 --- a/selftest.c +++ b/selftest.c @@ -12,28 +12,35 @@ struct utcp_connection *c; ssize_t do_recv(struct utcp_connection *x, const void *data, size_t len) { if(!len) { - if(errno) + if(errno) { fprintf(stderr, "%p Error: %s\n", x->utcp, strerror(errno)); - else + } else { fprintf(stderr, "%p Connection closed by peer\n", x->utcp); + } + if(x != c) { fprintf(stderr, "closing my side too...\n"); utcp_close(x); } + return -1; } - if(x == c) + if(x == c) { return write(0, data, len); - else + } else { return utcp_send(x, data, len); + } } bool do_pre_accept(struct utcp *utcp, uint16_t port) { (void)utcp; fprintf(stderr, "pre-accept\n"); - if(port != 7) + + if(port != 7) { return false; + } + return true; } @@ -45,15 +52,17 @@ void do_accept(struct utcp_connection *c, uint16_t port) { ssize_t do_send(struct utcp *utcp, const void *data, size_t len) { static int count = 0; + if(++count > 1000) { fprintf(stderr, "Too many packets!\n"); abort(); } - if(utcp == a) + if(utcp == a) { return utcp_recv(b, data, len); - else + } else { return utcp_recv(a, data, len); + } } int main(int argc, char *argv[]) { @@ -87,18 +96,21 @@ int main(int argc, char *argv[]) { ssize_t len = utcp_send(c, "Hello world!\n", 13); if(len != 13) { - if(len == -1) + if(len == -1) { fprintf(stderr, "Error: %s\n", strerror(errno)); - else + } else { fprintf(stderr, "Short write %zd!\n", len); + } } + len = utcp_send(c, "This is a test.\n", 16); if(len != 16) { - if(len == -1) + if(len == -1) { fprintf(stderr, "Error: %s\n", strerror(errno)); - else + } else { fprintf(stderr, "Short write %zd!\n", len); + } } fprintf(stderr, "closing...\n"); @@ -111,8 +123,10 @@ int main(int argc, char *argv[]) { char buf[20480] = "buf"; len = utcp_send(c, buf, sizeof(buf)); - if(len != 10240) + + if(len != 10240) { fprintf(stderr, "Error: utcp_send() returned %zd, expected 10240\n", len); + } fprintf(stderr, "closing...\n"); utcp_close(c); diff --git a/test.c b/test.c index 94c0d7c..81f45a5 100644 --- a/test.c +++ b/test.c @@ -52,6 +52,7 @@ void debug(const char *format, ...) { 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)); @@ -60,19 +61,24 @@ ssize_t do_recv(struct utcp_connection *c, const void *data, size_t len) { 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); } @@ -86,17 +92,21 @@ void do_accept(struct utcp_connection *nc, uint16_t port) { 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; @@ -115,8 +125,11 @@ ssize_t do_send(struct utcp *utcp, const void *data, size_t len) { 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; } @@ -124,64 +137,102 @@ int main(int argc, char *argv[]) { 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}, @@ -189,41 +240,56 @@ int main(int argc, char *argv[]) { }; 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); + } } } @@ -233,18 +299,25 @@ int main(int argc, char *argv[]) { 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"); } @@ -254,7 +327,9 @@ int main(int argc, char *argv[]) { }; utcp_close(c); + utcp_exit(u); + free(reorder_data); debug("Total bytes in: %ld, out: %ld\n", total_in, total_out); diff --git a/utcp.c b/utcp.c index f20d86e..b939dc8 100644 --- a/utcp.c +++ b/utcp.c @@ -45,12 +45,13 @@ #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) { @@ -69,6 +70,7 @@ static void debug(const char *format, ...) { 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; @@ -76,14 +78,22 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si 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); @@ -95,6 +105,7 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si *p++ = "0123456789ABCDEF"[data[i] >> 4]; *p++ = "0123456789ABCDEF"[data[i] & 15]; } + *p = 0; debug(" data=%s", str); @@ -109,19 +120,25 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si 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; } @@ -143,15 +160,19 @@ static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data 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 { @@ -159,18 +180,27 @@ static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data 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; } @@ -180,33 +210,47 @@ static ssize_t buffer_put(struct buffer *buf, const void *data, size_t 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; @@ -234,15 +278,20 @@ static int compare(const void *va, const void *vb) { 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, @@ -279,27 +328,37 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s 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); @@ -337,10 +396,11 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s } 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. @@ -362,8 +422,9 @@ static void update_rtt(struct utcp_connection *c, uint32_t rtt) { 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); } @@ -371,10 +432,12 @@ static void update_rtt(struct utcp_connection *c, uint32_t rtt) { 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); } @@ -385,8 +448,10 @@ static void stop_retransmit_timer(struct utcp_connection *c) { 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); @@ -447,14 +512,17 @@ static void ack(struct utcp_connection *c, bool sendatleastone) { 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; @@ -462,8 +530,10 @@ static void ack(struct utcp_connection *c, bool sendatleastone) { } *pkt; pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu); - if(!pkt) + + if(!pkt) { return; + } pkt->hdr.src = c->src; pkt->hdr.dst = c->dst; @@ -515,9 +585,11 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) { 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: @@ -530,8 +602,9 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) { // Exit early if we have nothing to send. - if(!len) + if(!len) { return 0; + } if(!data) { errno = EFAULT; @@ -541,6 +614,7 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) { // Add data to send buffer. len = buffer_put(&c->sndbuf, data, len); + if(len <= 0) { errno = EWOULDBLOCK; return 0; @@ -548,12 +622,16 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) { 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; } @@ -578,8 +656,10 @@ static void retransmit(struct utcp_connection *c) { } *pkt; pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu); - if(!pkt) + + if(!pkt) { return; + } pkt->hdr.src = c->src; pkt->hdr.dst = c->dst; @@ -587,68 +667,75 @@ static void retransmit(struct utcp_connection *c) { 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: @@ -675,6 +762,7 @@ 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; @@ -683,7 +771,7 @@ static void sack_consume(struct utcp_connection *c, size_t len) { 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++; @@ -702,16 +790,19 @@ static void sack_consume(struct utcp_connection *c, size_t len) { } } - 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++) { @@ -730,6 +821,7 @@ static void handle_out_of_order(struct utcp_connection *c, uint32_t offset, cons } else { debug("SACK entries full, dropping packet\n"); } + break; } else { // merge debug("Merge with start of SACK entry at %d\n", i); @@ -742,12 +834,14 @@ static void handle_out_of_order(struct utcp_connection *c, uint32_t offset, cons 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) { @@ -761,14 +855,16 @@ static void handle_in_order(struct utcp_connection *c, const void *data, size_t 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; } @@ -782,13 +878,16 @@ static void handle_incoming_data(struct utcp_connection *c, uint32_t seq, const } 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); + } } @@ -798,8 +897,9 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { return -1; } - if(!len) + if(!len) { return 0; + } if(!data) { errno = EFAULT; @@ -811,6 +911,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { // Drop packets smaller than the header struct hdr hdr; + if(len < sizeof(hdr)) { errno = EBADMSG; return -1; @@ -834,6 +935,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { const uint8_t *init = NULL; uint16_t aux = hdr.aux; + while(aux) { size_t auxlen = 4 * (aux >> 8) & 0xf; uint8_t auxtype = aux & 0xff; @@ -849,8 +951,10 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { errno = EBADMSG; return -1; } + init = data; break; + default: errno = EBADMSG; return -1; @@ -859,8 +963,9 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { len -= auxlen; data += auxlen; - if(!(aux & 0x800)) + if(!(aux & 0x800)) { break; + } if(len < 2) { errno = EBADMSG; @@ -881,8 +986,9 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { if(!c) { // Ignore RST packets - if(hdr.ctl & RST) + if(hdr.ctl & RST) { return 0; + } // Is it a SYN packet and are we LISTENing? @@ -895,6 +1001,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { // Try to allocate memory, otherwise send a RST back c = allocate_connection(utcp, hdr.dst, hdr.src); + if(!c) { len = 1; goto reset; @@ -906,6 +1013,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { len = 1; goto reset; } + c->flags = init[3] & 0x7; } else { c->flags = UTCP_TCP; @@ -928,6 +1036,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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; @@ -979,6 +1088,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { case LAST_ACK: case TIME_WAIT: break; + default: #ifdef UTCP_DEBUG abort(); @@ -990,16 +1100,17 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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; @@ -1012,9 +1123,12 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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; } @@ -1027,9 +1141,12 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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; } @@ -1038,46 +1155,65 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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(); @@ -1086,8 +1222,9 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { } } - if(!(hdr.ctl & ACK)) + if(!(hdr.ctl & ACK)) { goto skip_ack; + } // 3. Advance snd.una @@ -1112,13 +1249,14 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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); @@ -1126,39 +1264,49 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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. @@ -1175,10 +1323,12 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) { 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: @@ -1187,14 +1337,18 @@ 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: @@ -1205,6 +1359,7 @@ skip_ack: case TIME_WAIT: // Ehm, no. We should never receive a second SYN. return 0; + default: #ifdef UTCP_DEBUG abort(); @@ -1220,12 +1375,14 @@ skip_ack: 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); @@ -1243,16 +1400,19 @@ skip_ack: 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(); @@ -1274,23 +1434,28 @@ skip_ack: 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(); @@ -1322,6 +1487,7 @@ reset: swap_ports(&hdr); hdr.wnd = 0; hdr.aux = 0; + if(hdr.ctl & ACK) { hdr.seq = hdr.ack; hdr.ctl = RST; @@ -1330,6 +1496,7 @@ reset: hdr.seq = 0; hdr.ctl = RST | ACK; } + print_packet(utcp, "send", &hdr, sizeof(hdr)); utcp->send(utcp, &hdr, sizeof(hdr)); return 0; @@ -1338,6 +1505,7 @@ reset: 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; @@ -1356,12 +1524,14 @@ int utcp_shutdown(struct utcp_connection *c, int dir) { // 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: @@ -1377,9 +1547,11 @@ int utcp_shutdown(struct utcp_connection *c, int dir) { 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; @@ -1393,14 +1565,19 @@ int utcp_shutdown(struct utcp_connection *c, int dir) { 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; @@ -1426,6 +1603,7 @@ int utcp_abort(struct utcp_connection *c) { switch(c->state) { case CLOSED: return 0; + case LISTEN: case SYN_SENT: case CLOSING: @@ -1472,8 +1650,10 @@ struct timeval utcp_timeout(struct utcp *utcp) { 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) { @@ -1482,14 +1662,18 @@ struct timeval utcp_timeout(struct utcp *utcp) { 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; } @@ -1501,32 +1685,40 @@ struct timeval utcp_timeout(struct utcp *utcp) { 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; } @@ -1538,8 +1730,10 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_ } struct utcp *utcp = calloc(1, sizeof(*utcp)); - if(!utcp) + + if(!utcp) { return NULL; + } utcp->accept = accept; utcp->pre_accept = pre_accept; @@ -1553,17 +1747,23 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_ } 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); } @@ -1574,24 +1774,33 @@ uint16_t utcp_get_mtu(struct utcp *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) { @@ -1599,8 +1808,9 @@ 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) { @@ -1608,18 +1818,23 @@ 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) { @@ -1627,18 +1842,23 @@ 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) { @@ -1646,8 +1866,9 @@ 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) { @@ -1655,8 +1876,9 @@ 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) { @@ -1664,13 +1886,15 @@ 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) {