#include <stdbool.h>
#include <string.h>
#include <unistd.h>
-#include <sys/time.h>
-#include <sys/socket.h>
+#include <time.h>
#include "utcp_priv.h"
#undef poll
#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)
+#ifndef UTCP_CLOCK
+#if defined(CLOCK_MONOTONIC_RAW) && defined(__x86_64__)
+#define UTCP_CLOCK CLOCK_MONOTONIC_RAW
+#else
+#define UTCP_CLOCK CLOCK_MONOTONIC
+#endif
#endif
+static void timespec_sub(const struct timespec *a, const struct timespec *b, struct timespec *r) {
+ r->tv_sec = a->tv_sec - b->tv_sec;
+ r->tv_nsec = a->tv_nsec - b->tv_nsec;
+
+ if(r->tv_nsec < 0) {
+ r->tv_sec--, r->tv_nsec += NSEC_PER_SEC;
+ }
+}
+
+static int32_t timespec_diff_usec(const struct timespec *a, const struct timespec *b) {
+ return (a->tv_sec - b->tv_sec) * 1000000 + (a->tv_nsec - b->tv_nsec) / 1000;
+}
+
+static bool timespec_lt(const struct timespec *a, const struct timespec *b) {
+ if(a->tv_sec == b->tv_sec) {
+ return a->tv_nsec < b->tv_nsec;
+ } else {
+ return a->tv_sec < b->tv_sec;
+ }
+}
+
+static void timespec_clear(struct timespec *a) {
+ a->tv_sec = 0;
+ a->tv_nsec = 0;
+}
+
+static bool timespec_isset(const struct timespec *a) {
+ return a->tv_sec;
+}
+
+static long CLOCK_GRANULARITY; // usec
+
+static inline size_t min(size_t a, size_t b) {
+ return a < b ? a : b;
+}
+
static inline size_t max(size_t a, size_t b) {
return a > b ? a : b;
}
#ifdef UTCP_DEBUG
#include <stdarg.h>
-static void debug(const char *format, ...) {
+#ifndef UTCP_DEBUG_DATALEN
+#define UTCP_DEBUG_DATALEN 20
+#endif
+
+static void debug(struct utcp_connection *c, const char *format, ...) {
+ struct timespec tv;
+ char buf[1024];
+ int len;
+
+ clock_gettime(CLOCK_REALTIME, &tv);
+ len = snprintf(buf, sizeof(buf), "%ld.%06lu %u:%u ", (long)tv.tv_sec, tv.tv_nsec / 1000, c ? c->src : 0, c ? c->dst : 0);
va_list ap;
va_start(ap, format);
- vfprintf(stderr, format, ap);
+ len += vsnprintf(buf + len, sizeof(buf) - len, format, ap);
va_end(ap);
+
+ if(len > 0 && (size_t)len < sizeof(buf)) {
+ fwrite(buf, len, 1, stderr);
+ }
}
-static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, size_t len) {
+static void print_packet(struct utcp_connection *c, 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);
+ debug(c, "%s: short packet (%lu bytes)\n", 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) {
- debug("SYN");
- }
-
- if(hdr.ctl & RST) {
- debug("RST");
- }
+ uint32_t datalen;
- if(hdr.ctl & FIN) {
- debug("FIN");
+ if(len > sizeof(hdr)) {
+ datalen = min(len - sizeof(hdr), UTCP_DEBUG_DATALEN);
+ } else {
+ datalen = 0;
}
- if(hdr.ctl & ACK) {
- debug("ACK");
- }
- if(len > sizeof(hdr)) {
- uint32_t datalen = len - sizeof(hdr);
- const uint8_t *data = (uint8_t *)pkt + sizeof(hdr);
- char str[datalen * 2 + 1];
- char *p = str;
+ const uint8_t *data = (uint8_t *)pkt + sizeof(hdr);
+ char str[datalen * 2 + 1];
+ char *p = str;
- for(uint32_t i = 0; i < datalen; i++) {
- *p++ = "0123456789ABCDEF"[data[i] >> 4];
- *p++ = "0123456789ABCDEF"[data[i] & 15];
- }
+ for(uint32_t i = 0; i < datalen; i++) {
+ *p++ = "0123456789ABCDEF"[data[i] >> 4];
+ *p++ = "0123456789ABCDEF"[data[i] & 15];
+ }
- *p = 0;
+ *p = 0;
- debug(" data=%s", str);
- }
+ debug(c, "%s: len %lu src %u dst %u seq %u ack %u wnd %u aux %x ctl %s%s%s%s%s data %s\n",
+ dir, (unsigned long)len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd, hdr.aux,
+ hdr.ctl & SYN ? "SYN" : "",
+ hdr.ctl & RST ? "RST" : "",
+ hdr.ctl & FIN ? "FIN" : "",
+ hdr.ctl & ACK ? "ACK" : "",
+ hdr.ctl & MF ? "MF" : "",
+ str
+ );
+}
- debug("\n");
+static void debug_cwnd(struct utcp_connection *c) {
+ debug(c, "snd.cwnd %u snd.ssthresh %u\n", c->snd.cwnd, ~c->snd.ssthresh ? c->snd.ssthresh : 0);
}
#else
#define debug(...) do {} while(0)
#define print_packet(...) do {} while(0)
+#define debug_cwnd(...) do {} while(0)
#endif
static void set_state(struct utcp_connection *c, enum state state) {
c->state = state;
if(state == ESTABLISHED) {
- timerclear(&c->conn_timeout);
+ timespec_clear(&c->conn_timeout);
}
- debug("%p new state: %s\n", c->utcp, strstate[state]);
+ debug(c, "state %s\n", strstate[state]);
}
static bool fin_wanted(struct utcp_connection *c, uint32_t seq) {
}
// Buffer functions
-// TODO: convert to ringbuffers to avoid memmove() operations.
+static bool buffer_wraps(struct buffer *buf) {
+ return buf->size - buf->offset < buf->used;
+}
+
+static bool buffer_resize(struct buffer *buf, uint32_t newsize) {
+ char *newdata = realloc(buf->data, newsize);
+
+ if(!newdata) {
+ return false;
+ }
+
+ buf->data = newdata;
+
+ if(buffer_wraps(buf)) {
+ // Shift the right part of the buffer until it hits the end of the new buffer.
+ // Old situation:
+ // [345......012]
+ // New situation:
+ // [345.........|........012]
+ uint32_t tailsize = buf->size - buf->offset;
+ uint32_t newoffset = newsize - tailsize;
+ memmove(buf->data + newoffset, buf->data + buf->offset, tailsize);
+ buf->offset = newoffset;
+ }
+
+ buf->size = newsize;
+ return true;
+}
// Store data into the buffer
static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data, size_t len) {
- debug("buffer_put_at %lu %lu %lu\n", (unsigned long)buf->used, (unsigned long)offset, (unsigned long)len);
+ debug(NULL, "buffer_put_at %lu %lu %lu\n", (unsigned long)buf->used, (unsigned long)offset, (unsigned long)len);
+ // Ensure we don't store more than maxsize bytes in total
size_t required = offset + len;
if(required > buf->maxsize) {
required = buf->maxsize;
}
+ // Check if we need to resize the buffer
if(required > buf->size) {
size_t newsize = buf->size;
if(!newsize) {
- newsize = required;
- } else {
- do {
- newsize *= 2;
- } while(newsize < required);
+ newsize = 4096;
}
+ do {
+ newsize *= 2;
+ } while(newsize < required);
+
if(newsize > buf->maxsize) {
newsize = buf->maxsize;
}
- char *newdata = realloc(buf->data, newsize);
-
- if(!newdata) {
+ if(!buffer_resize(buf, newsize)) {
return -1;
}
+ }
- buf->data = newdata;
- buf->size = newsize;
+ uint32_t realoffset = buf->offset + offset;
+
+ if(buf->size - buf->offset <= offset) {
+ // The offset wrapped
+ realoffset -= buf->size;
}
- memcpy(buf->data + offset, data, len);
+ if(buf->size - realoffset < len) {
+ // The new chunk of data must be wrapped
+ memcpy(buf->data + realoffset, data, buf->size - realoffset);
+ memcpy(buf->data, (char *)data + buf->size - realoffset, len - (buf->size - realoffset));
+ } else {
+ memcpy(buf->data + realoffset, data, len);
+ }
if(required > buf->used) {
buf->used = required;
return buffer_put_at(buf, buf->used, data, 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) {
- len = buf->used;
+// Copy data from the buffer without removing it.
+static ssize_t buffer_copy(struct buffer *buf, void *data, size_t offset, size_t len) {
+ // Ensure we don't copy more than is actually stored in the buffer
+ if(offset >= buf->used) {
+ return 0;
+ }
+
+ if(buf->used - offset < len) {
+ len = buf->used - offset;
}
- if(data) {
- memcpy(data, buf->data, len);
+ uint32_t realoffset = buf->offset + offset;
+
+ if(buf->size - buf->offset <= offset) {
+ // The offset wrapped
+ realoffset -= buf->size;
}
- if(len < buf->used) {
- memmove(buf->data, buf->data + len, buf->used - len);
+ if(buf->size - realoffset < len) {
+ // The data is wrapped
+ memcpy(data, buf->data + realoffset, buf->size - realoffset);
+ memcpy((char *)data + buf->size - realoffset, buf->data, len - (buf->size - realoffset));
+ } else {
+ memcpy(data, buf->data + realoffset, 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) {
+static ssize_t buffer_call(struct utcp_connection *c, struct buffer *buf, size_t offset, size_t len) {
+ if(!c->recv) {
+ return len;
+ }
+
+ // Ensure we don't copy more than is actually stored in the buffer
if(offset >= buf->used) {
return 0;
}
- if(offset + len > buf->used) {
+ if(buf->used - offset < len) {
len = buf->used - offset;
}
- memcpy(data, buf->data + offset, len);
- return len;
-}
+ uint32_t realoffset = buf->offset + offset;
-static bool buffer_init(struct buffer *buf, uint32_t len, uint32_t maxlen) {
- memset(buf, 0, sizeof(*buf));
+ if(buf->size - buf->offset <= offset) {
+ // The offset wrapped
+ realoffset -= buf->size;
+ }
- if(len) {
- buf->data = malloc(len);
+ if(buf->size - realoffset < len) {
+ // The data is wrapped
+ ssize_t rx1 = c->recv(c, buf->data + realoffset, buf->size - realoffset);
+
+ if(rx1 < buf->size - realoffset) {
+ return rx1;
+ }
- if(!buf->data) {
- return false;
+ // The channel might have been closed by the previous callback
+ if(!c->recv) {
+ return len;
}
+
+ ssize_t rx2 = c->recv(c, buf->data, len - (buf->size - realoffset));
+
+ if(rx2 < 0) {
+ return rx2;
+ } else {
+ return rx1 + rx2;
+ }
+ } else {
+ return c->recv(c, buf->data + realoffset, len);
}
+}
- buf->size = len;
- buf->maxsize = maxlen;
- return true;
+// Discard data from the buffer.
+static ssize_t buffer_discard(struct buffer *buf, size_t len) {
+ if(buf->used < len) {
+ len = buf->used;
+ }
+
+ if(buf->size - buf->offset <= len) {
+ buf->offset -= buf->size;
+ }
+
+ if(buf->used == len) {
+ buf->offset = 0;
+ } else {
+ buf->offset += len;
+ }
+
+ buf->used -= len;
+
+ return len;
+}
+
+static void buffer_clear(struct buffer *buf) {
+ buf->used = 0;
+ buf->offset = 0;
+}
+
+static bool buffer_set_size(struct buffer *buf, uint32_t minsize, uint32_t maxsize) {
+ if(maxsize < minsize) {
+ maxsize = minsize;
+ }
+
+ buf->maxsize = maxsize;
+
+ return buf->size >= minsize || buffer_resize(buf, minsize);
}
static void buffer_exit(struct buffer *buf) {
}
static uint32_t buffer_free(const struct buffer *buf) {
- return buf->maxsize - buf->used;
+ return buf->maxsize > buf->used ? buf->maxsize - buf->used : 0;
}
// Connections are stored in a sorted list.
return NULL;
}
- if(!buffer_init(&c->sndbuf, DEFAULT_SNDBUFSIZE, DEFAULT_MAXSNDBUFSIZE)) {
+ if(!buffer_set_size(&c->sndbuf, DEFAULT_SNDBUFSIZE, DEFAULT_MAXSNDBUFSIZE)) {
free(c);
return NULL;
}
- if(!buffer_init(&c->rcvbuf, DEFAULT_RCVBUFSIZE, DEFAULT_MAXRCVBUFSIZE)) {
+ if(!buffer_set_size(&c->rcvbuf, DEFAULT_RCVBUFSIZE, DEFAULT_MAXRCVBUFSIZE)) {
buffer_exit(&c->sndbuf);
free(c);
return NULL;
#endif
c->snd.una = c->snd.iss;
c->snd.nxt = c->snd.iss + 1;
- c->rcv.wnd = utcp->mtu;
c->snd.last = c->snd.nxt;
- c->snd.cwnd = utcp->mtu;
+ c->snd.cwnd = (utcp->mss > 2190 ? 2 : utcp->mss > 1095 ? 3 : 4) * utcp->mss;
+ c->snd.ssthresh = ~0;
+ debug_cwnd(c);
+ c->srtt = 0;
+ c->rttvar = 0;
+ c->rto = START_RTO;
c->utcp = utcp;
// Add it to the sorted list of connections
// Update RTT variables. See RFC 6298.
static void update_rtt(struct utcp_connection *c, uint32_t rtt) {
if(!rtt) {
- debug("invalid rtt\n");
+ debug(c, "invalid rtt\n");
return;
}
- struct utcp *utcp = c->utcp;
-
- if(!utcp->srtt) {
- utcp->srtt = rtt;
- utcp->rttvar = rtt / 2;
- utcp->rto = rtt + max(2 * rtt, CLOCK_GRANULARITY);
+ if(!c->srtt) {
+ c->srtt = rtt;
+ c->rttvar = rtt / 2;
} else {
- utcp->rttvar = (utcp->rttvar * 3 + absdiff(utcp->srtt, rtt)) / 4;
- utcp->srtt = (utcp->srtt * 7 + rtt) / 8;
- utcp->rto = utcp->srtt + max(utcp->rttvar, CLOCK_GRANULARITY);
+ c->rttvar = (c->rttvar * 3 + absdiff(c->srtt, rtt)) / 4;
+ c->srtt = (c->srtt * 7 + rtt) / 8;
}
- if(utcp->rto > MAX_RTO) {
- utcp->rto = MAX_RTO;
+ c->rto = c->srtt + max(4 * c->rttvar, CLOCK_GRANULARITY);
+
+ if(c->rto > MAX_RTO) {
+ c->rto = MAX_RTO;
}
- debug("rtt %u srtt %u rttvar %u rto %u\n", rtt, utcp->srtt, utcp->rttvar, utcp->rto);
+ debug(c, "rtt %u srtt %u rttvar %u rto %u\n", rtt, c->srtt, c->rttvar, c->rto);
}
static void start_retransmit_timer(struct utcp_connection *c) {
- gettimeofday(&c->rtrx_timeout, NULL);
- c->rtrx_timeout.tv_usec += c->utcp->rto;
+ clock_gettime(UTCP_CLOCK, &c->rtrx_timeout);
+
+ uint32_t rto = c->rto;
+
+ while(rto > USEC_PER_SEC) {
+ c->rtrx_timeout.tv_sec++;
+ rto -= USEC_PER_SEC;
+ }
+
+ c->rtrx_timeout.tv_nsec += rto * 1000;
- while(c->rtrx_timeout.tv_usec >= 1000000) {
- c->rtrx_timeout.tv_usec -= 1000000;
+ if(c->rtrx_timeout.tv_nsec >= NSEC_PER_SEC) {
+ c->rtrx_timeout.tv_nsec -= NSEC_PER_SEC;
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);
+ debug(c, "rtrx_timeout %ld.%06lu\n", c->rtrx_timeout.tv_sec, c->rtrx_timeout.tv_nsec);
}
static void stop_retransmit_timer(struct utcp_connection *c) {
- timerclear(&c->rtrx_timeout);
- debug("timeout cleared\n");
+ timespec_clear(&c->rtrx_timeout);
+ debug(c, "rtrx_timeout cleared\n");
}
struct utcp_connection *utcp_connect_ex(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv, uint32_t flags) {
return NULL;
}
- assert((flags & ~0xf) == 0);
+ assert((flags & ~0x1f) == 0);
c->flags = flags;
c->recv = recv;
pkt.hdr.dst = c->dst;
pkt.hdr.seq = c->snd.iss;
pkt.hdr.ack = 0;
- pkt.hdr.wnd = c->rcv.wnd;
+ pkt.hdr.wnd = c->rcvbuf.maxsize;
pkt.hdr.ctl = SYN;
pkt.hdr.aux = 0x0101;
pkt.init[0] = 1;
set_state(c, SYN_SENT);
- print_packet(utcp, "send", &pkt, sizeof(pkt));
+ print_packet(c, "send", &pkt, sizeof(pkt));
utcp->send(utcp, &pkt, sizeof(pkt));
- gettimeofday(&c->conn_timeout, NULL);
+ clock_gettime(UTCP_CLOCK, &c->conn_timeout);
c->conn_timeout.tv_sec += utcp->timeout;
start_retransmit_timer(c);
void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
if(c->reapable || c->state != SYN_RECEIVED) {
- debug("Error: accept() called on invalid connection %p in state %s\n", c, strstate[c->state]);
+ debug(c, "accept() called on invalid connection in state %s\n", c, strstate[c->state]);
return;
}
- debug("%p accepted, %p %p\n", c, recv, priv);
+ debug(c, "accepted %p %p\n", c, recv, priv);
c->recv = recv;
c->priv = priv;
set_state(c, ESTABLISHED);
static void ack(struct utcp_connection *c, bool sendatleastone) {
int32_t left = seqdiff(c->snd.last, c->snd.nxt);
- int32_t cwndleft = c->snd.cwnd - seqdiff(c->snd.nxt, c->snd.una);
- debug("cwndleft = %d\n", cwndleft);
+ int32_t cwndleft = is_reliable(c) ? min(c->snd.cwnd, c->snd.wnd) - seqdiff(c->snd.nxt, c->snd.una) : MAX_UNRELIABLE_SIZE;
assert(left >= 0);
if(cwndleft <= 0) {
- cwndleft = 0;
- }
-
- if(cwndleft < left) {
+ left = 0;
+ } else if(cwndleft < left) {
left = cwndleft;
+
+ if(!sendatleastone || cwndleft > c->utcp->mss) {
+ left -= left % c->utcp->mss;
+ }
}
+ debug(c, "cwndleft %d left %d\n", cwndleft, left);
+
if(!left && !sendatleastone) {
return;
}
struct {
struct hdr hdr;
uint8_t data[];
- } *pkt;
-
- pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu);
-
- if(!pkt) {
- return;
- }
+ } *pkt = c->utcp->pkt;
pkt->hdr.src = c->src;
pkt->hdr.dst = c->dst;
pkt->hdr.ack = c->rcv.nxt;
- pkt->hdr.wnd = c->snd.wnd;
+ pkt->hdr.wnd = is_reliable(c) ? c->rcvbuf.maxsize : 0;
pkt->hdr.ctl = ACK;
pkt->hdr.aux = 0;
do {
- uint32_t seglen = left > c->utcp->mtu ? c->utcp->mtu : left;
+ uint32_t seglen = left > c->utcp->mss ? c->utcp->mss : left;
pkt->hdr.seq = c->snd.nxt;
buffer_copy(&c->sndbuf, pkt->data, seqdiff(c->snd.nxt, c->snd.una), seglen);
c->snd.nxt += seglen;
left -= seglen;
+ if(!is_reliable(c)) {
+ if(left) {
+ pkt->hdr.ctl |= MF;
+ } else {
+ pkt->hdr.ctl &= ~MF;
+ }
+ }
+
if(seglen && fin_wanted(c, c->snd.nxt)) {
seglen--;
pkt->hdr.ctl |= FIN;
if(!c->rtt_start.tv_sec) {
// Start RTT measurement
- gettimeofday(&c->rtt_start, NULL);
+ clock_gettime(UTCP_CLOCK, &c->rtt_start);
c->rtt_seq = pkt->hdr.seq + seglen;
- debug("Starting RTT measurement, expecting ack %u\n", c->rtt_seq);
+ debug(c, "starting RTT measurement, expecting ack %u\n", c->rtt_seq);
}
- print_packet(c->utcp, "send", pkt, sizeof(pkt->hdr) + seglen);
+ print_packet(c, "send", pkt, sizeof(pkt->hdr) + seglen);
c->utcp->send(c->utcp, pkt, sizeof(pkt->hdr) + seglen);
- } while(left);
- free(pkt);
+ if(left && !is_reliable(c)) {
+ pkt->hdr.wnd += seglen;
+ }
+ } while(left);
}
ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
if(c->reapable) {
- debug("Error: send() called on closed connection %p\n", c);
+ debug(c, "send() called on closed connection\n");
errno = EBADF;
return -1;
}
switch(c->state) {
case CLOSED:
case LISTEN:
- debug("Error: send() called on unconnected connection %p\n", c);
+ debug(c, "send() called on unconnected connection\n");
errno = ENOTCONN;
return -1;
case CLOSING:
case LAST_ACK:
case TIME_WAIT:
- debug("Error: send() called on closing connection %p\n", c);
+ debug(c, "send() called on closed connection\n");
errno = EPIPE;
return -1;
}
return -1;
}
+ // Check if we need to be able to buffer all data
+
+ if(c->flags & UTCP_NO_PARTIAL) {
+ if(len > buffer_free(&c->sndbuf)) {
+ if(len > c->sndbuf.maxsize) {
+ errno = EMSGSIZE;
+ return -1;
+ } else {
+ errno = EWOULDBLOCK;
+ return 0;
+ }
+ }
+ }
+
// Add data to send buffer.
- len = buffer_put(&c->sndbuf, data, len);
+ if(is_reliable(c)) {
+ len = buffer_put(&c->sndbuf, data, len);
+ } else if(c->state != SYN_SENT && c->state != SYN_RECEIVED) {
+ if(len > MAX_UNRELIABLE_SIZE || buffer_put(&c->sndbuf, data, len) != (ssize_t)len) {
+ errno = EMSGSIZE;
+ return -1;
+ }
+ } else {
+ return 0;
+ }
if(len <= 0) {
- errno = EWOULDBLOCK;
- return 0;
+ if(is_reliable(c)) {
+ errno = EWOULDBLOCK;
+ return 0;
+ } else {
+ return len;
+ }
}
c->snd.last += len;
// Don't send anything yet if the connection has not fully established yet
- if (c->state == SYN_SENT || c->state == SYN_RECEIVED)
+ if(c->state == SYN_SENT || c->state == SYN_RECEIVED) {
return 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);
+ buffer_discard(&c->sndbuf, c->sndbuf.used);
}
- if(is_reliable(c) && !timerisset(&c->rtrx_timeout)) {
+ if(is_reliable(c) && !timespec_isset(&c->rtrx_timeout)) {
start_retransmit_timer(c);
}
+ if(is_reliable(c) && !timespec_isset(&c->conn_timeout)) {
+ clock_gettime(UTCP_CLOCK, &c->conn_timeout);
+ c->conn_timeout.tv_sec += c->utcp->timeout;
+ }
+
return len;
}
hdr->dst = tmp;
}
-static void retransmit(struct utcp_connection *c) {
+static void fast_retransmit(struct utcp_connection *c) {
if(c->state == CLOSED || c->snd.last == c->snd.una) {
- debug("Retransmit() called but nothing to retransmit!\n");
- stop_retransmit_timer(c);
+ debug(c, "fast_retransmit() called but nothing to retransmit!\n");
return;
}
struct {
struct hdr hdr;
uint8_t data[];
- } *pkt;
+ } *pkt = c->utcp->pkt;
+
+ pkt->hdr.src = c->src;
+ pkt->hdr.dst = c->dst;
+ pkt->hdr.wnd = c->rcvbuf.maxsize;
+ pkt->hdr.aux = 0;
+
+ switch(c->state) {
+ 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 = min(seqdiff(c->snd.last, c->snd.una), utcp->mss);
+
+ if(fin_wanted(c, c->snd.una + len)) {
+ len--;
+ pkt->hdr.ctl |= FIN;
+ }
+
+ buffer_copy(&c->sndbuf, pkt->data, 0, len);
+ print_packet(c, "rtrx", pkt, sizeof(pkt->hdr) + len);
+ utcp->send(utcp, pkt, sizeof(pkt->hdr) + len);
+ break;
- pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu);
+ default:
+ break;
+ }
+}
- if(!pkt) {
+static void retransmit(struct utcp_connection *c) {
+ if(c->state == CLOSED || c->snd.last == c->snd.una) {
+ debug(c, "retransmit() called but nothing to retransmit!\n");
+ stop_retransmit_timer(c);
return;
}
+ struct utcp *utcp = c->utcp;
+
+ if(utcp->retransmit) {
+ utcp->retransmit(c);
+ }
+
+ struct {
+ struct hdr hdr;
+ uint8_t data[];
+ } *pkt = c->utcp->pkt;
+
pkt->hdr.src = c->src;
pkt->hdr.dst = c->dst;
- pkt->hdr.wnd = c->rcv.wnd;
+ pkt->hdr.wnd = c->rcvbuf.maxsize;
pkt->hdr.aux = 0;
switch(c->state) {
pkt->data[1] = 0;
pkt->data[2] = 0;
pkt->data[3] = c->flags & 0x7;
- print_packet(c->utcp, "rtrx", pkt, sizeof(pkt->hdr) + 4);
+ print_packet(c, "rtrx", pkt, sizeof(pkt->hdr) + 4);
utcp->send(utcp, pkt, sizeof(pkt->hdr) + 4);
break;
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));
+ print_packet(c, "rtrx", pkt, sizeof(pkt->hdr));
utcp->send(utcp, pkt, sizeof(pkt->hdr));
break;
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;
- }
+ uint32_t len = min(seqdiff(c->snd.last, c->snd.una), utcp->mss);
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
+ // RFC 5681 slow start after timeout
+ uint32_t flightsize = seqdiff(c->snd.nxt, c->snd.una);
+ c->snd.ssthresh = max(flightsize / 2, utcp->mss * 2); // eq. 4
+ c->snd.cwnd = utcp->mss;
+ debug_cwnd(c);
+
buffer_copy(&c->sndbuf, pkt->data, 0, len);
- print_packet(c->utcp, "rtrx", pkt, sizeof(pkt->hdr) + len);
+ print_packet(c, "rtrx", pkt, sizeof(pkt->hdr) + len);
utcp->send(utcp, pkt, sizeof(pkt->hdr) + len);
+
+ c->snd.nxt = c->snd.una + len;
break;
case CLOSED:
}
start_retransmit_timer(c);
- utcp->rto *= 2;
+ c->rto *= 2;
- if(utcp->rto > MAX_RTO) {
- utcp->rto = MAX_RTO;
+ if(c->rto > MAX_RTO) {
+ c->rto = MAX_RTO;
}
c->rtt_start.tv_sec = 0; // invalidate RTT timer
+ c->dupack = 0; // cancel any ongoing fast recovery
cleanup:
- free(pkt);
+ return;
}
/* Update receive buffer and SACK entries after consuming data.
* - the SACK entry is completely before ^, in that case delete it.
*/
static void sack_consume(struct utcp_connection *c, size_t len) {
- debug("sack_consume %lu\n", (unsigned long)len);
+ debug(c, "sack_consume %lu\n", (unsigned long)len);
if(len > c->rcvbuf.used) {
- debug("All SACK entries consumed");
+ debug(c, "all SACK entries consumed\n");
c->sacks[0].len = 0;
return;
}
- buffer_get(&c->rcvbuf, NULL, len);
+ buffer_discard(&c->rcvbuf, len);
for(int i = 0; i < NSACKS && c->sacks[i].len;) {
if(len < c->sacks[i].offset) {
}
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);
+ debug(c, "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);
+ debug(c, "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) {
- abort();
+ if(rxd <= 0) {
+ debug(c, "packet outside receive buffer, dropping\n");
+ return;
+ }
+
+ if((size_t)rxd < len) {
+ debug(c, "packet partially outside receive buffer\n");
+ len = rxd;
}
// Make note of where we put it.
for(int i = 0; i < NSACKS; i++) {
if(!c->sacks[i].len) { // nothing to merge, add new entry
- debug("New SACK entry %d\n", i);
+ debug(c, "new SACK entry %d\n", i);
c->sacks[i].offset = offset;
c->sacks[i].len = rxd;
break;
} else if(offset < c->sacks[i].offset) {
if(offset + rxd < c->sacks[i].offset) { // insert before
if(!c->sacks[NSACKS - 1].len) { // only if room left
- debug("Insert SACK entry at %d\n", i);
+ debug(c, "insert SACK entry at %d\n", i);
memmove(&c->sacks[i + 1], &c->sacks[i], (NSACKS - i - 1) * sizeof(c->sacks)[i]);
c->sacks[i].offset = offset;
c->sacks[i].len = rxd;
} else {
- debug("SACK entries full, dropping packet\n");
+ debug(c, "SACK entries full, dropping packet\n");
}
break;
} else { // merge
- debug("Merge with start of SACK entry at %d\n", i);
+ debug(c, "merge with start of SACK entry at %d\n", i);
c->sacks[i].offset = offset;
break;
}
} else if(offset <= c->sacks[i].offset + c->sacks[i].len) {
if(offset + rxd > c->sacks[i].offset + c->sacks[i].len) { // merge
- debug("Merge with end of SACK entry at %d\n", i);
+ debug(c, "merge with end of SACK entry at %d\n", i);
c->sacks[i].len = offset + rxd - c->sacks[i].offset;
// TODO: handle potential merge with next entry
}
}
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);
+ debug(c, "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) {
- // Check if we can process out-of-order data now.
- if(c->sacks[0].len && len >= c->sacks[0].offset) { // TODO: handle overlap with second SACK
- debug("incoming packet len %lu connected with SACK at %u\n", (unsigned long)len, c->sacks[0].offset);
- buffer_put_at(&c->rcvbuf, 0, data, len); // TODO: handle return value
- len = max(len, c->sacks[0].offset + c->sacks[0].len);
- data = c->rcvbuf.data;
- }
-
if(c->recv) {
ssize_t rxd = c->recv(c, data, len);
- if(rxd < 0 || (size_t)rxd != len) {
+ if(rxd != (ssize_t)len) {
// TODO: handle the application not accepting all data.
abort();
}
}
+ // Check if we can process out-of-order data now.
+ if(c->sacks[0].len && len >= c->sacks[0].offset) {
+ debug(c, "incoming packet len %lu connected with SACK at %u\n", (unsigned long)len, c->sacks[0].offset);
+
+ if(len < c->sacks[0].offset + c->sacks[0].len) {
+ size_t offset = len;
+ len = c->sacks[0].offset + c->sacks[0].len;
+ size_t remainder = len - offset;
+
+ ssize_t rxd = buffer_call(c, &c->rcvbuf, offset, remainder);
+
+ if(rxd != (ssize_t)remainder) {
+ // TODO: handle the application not accepting all data.
+ abort();
+ }
+ }
+ }
+
if(c->rcvbuf.used) {
sack_consume(c, len);
}
c->rcv.nxt += len;
}
+static void handle_unreliable(struct utcp_connection *c, const struct hdr *hdr, const void *data, size_t len) {
+ // Fast path for unfragmented packets
+ if(!hdr->wnd && !(hdr->ctl & MF)) {
+ if(c->recv) {
+ c->recv(c, data, len);
+ }
-static void handle_incoming_data(struct utcp_connection *c, uint32_t seq, const void *data, size_t len) {
- if(!is_reliable(c)) {
- c->recv(c, data, len);
- c->rcv.nxt = seq + len;
+ c->rcv.nxt = hdr->seq + len;
return;
}
- uint32_t offset = seqdiff(seq, c->rcv.nxt);
+ // Ensure reassembled packet are not larger than 64 kiB
+ if(hdr->wnd >= MAX_UNRELIABLE_SIZE || hdr->wnd + len > MAX_UNRELIABLE_SIZE) {
+ return;
+ }
- if(offset + len > c->rcvbuf.maxsize) {
- abort();
+ // Don't accept out of order fragments
+ if(hdr->wnd && hdr->seq != c->rcv.nxt) {
+ return;
+ }
+
+ // Reset the receive buffer for the first fragment
+ if(!hdr->wnd) {
+ buffer_clear(&c->rcvbuf);
}
+ ssize_t rxd = buffer_put_at(&c->rcvbuf, hdr->wnd, data, len);
+
+ if(rxd != (ssize_t)len) {
+ return;
+ }
+
+ // Send the packet if it's the final fragment
+ if(!(hdr->ctl & MF)) {
+ buffer_call(c, &c->rcvbuf, 0, hdr->wnd + len);
+ }
+
+ c->rcv.nxt = hdr->seq + len;
+}
+
+static void handle_incoming_data(struct utcp_connection *c, const struct hdr *hdr, const void *data, size_t len) {
+ if(!is_reliable(c)) {
+ handle_unreliable(c, hdr, data, len);
+ return;
+ }
+
+ uint32_t offset = seqdiff(hdr->seq, c->rcv.nxt);
+
if(offset) {
handle_out_of_order(c, offset, data, len);
} else {
return -1;
}
- print_packet(utcp, "recv", data, len);
-
// Drop packets smaller than the header
struct hdr hdr;
if(len < sizeof(hdr)) {
+ print_packet(NULL, "recv", data, len);
errno = EBADMSG;
return -1;
}
// Make a copy from the potentially unaligned data to a struct hdr
memcpy(&hdr, ptr, sizeof(hdr));
+
+ // Try to match the packet to an existing connection
+
+ struct utcp_connection *c = find_connection(utcp, hdr.dst, hdr.src);
+ print_packet(c, "recv", data, len);
+
+ // Process the header
+
ptr += sizeof(hdr);
len -= sizeof(hdr);
// Drop packets with an unknown CTL flag
- if(hdr.ctl & ~(SYN | ACK | RST | FIN)) {
+ if(hdr.ctl & ~(SYN | ACK | RST | FIN | MF)) {
+ print_packet(NULL, "recv", data, len);
errno = EBADMSG;
return -1;
}
ptr += 2;
}
- // Try to match the packet to an existing connection
-
- struct utcp_connection *c = find_connection(utcp, hdr.dst, hdr.src);
+ bool has_data = len || (hdr.ctl & (SYN | FIN));
// Is it for a new connection?
c->flags = UTCP_TCP;
}
+synack:
// Return SYN+ACK, go to SYN_RECEIVED state
c->snd.wnd = hdr.wnd;
c->rcv.irs = hdr.seq;
pkt.hdr.dst = c->dst;
pkt.hdr.ack = c->rcv.irs + 1;
pkt.hdr.seq = c->snd.iss;
- pkt.hdr.wnd = c->rcv.wnd;
+ pkt.hdr.wnd = c->rcvbuf.maxsize;
pkt.hdr.ctl = SYN | ACK;
if(init) {
pkt.data[1] = 0;
pkt.data[2] = 0;
pkt.data[3] = c->flags & 0x7;
- print_packet(c->utcp, "send", &pkt, sizeof(hdr) + 4);
+ print_packet(c, "send", &pkt, sizeof(hdr) + 4);
utcp->send(utcp, &pkt, sizeof(hdr) + 4);
} else {
pkt.hdr.aux = 0;
- print_packet(c->utcp, "send", &pkt, sizeof(hdr));
+ print_packet(c, "send", &pkt, sizeof(hdr));
utcp->send(utcp, &pkt, sizeof(hdr));
}
+
+ start_retransmit_timer(c);
} else {
// No, we don't want your packets, send a RST back
len = 1;
return 0;
}
- debug("%p state %s\n", c->utcp, strstate[c->state]);
+ debug(c, "state %s\n", strstate[c->state]);
// In case this is for a CLOSED connection, ignore the packet.
// TODO: make it so incoming packets can never match a CLOSED connection.
if(c->state == CLOSED) {
- debug("Got packet for closed connection\n");
+ debug(c, "got packet for closed connection\n");
return 0;
}
// It is for an existing connection.
- uint32_t prevrcvnxt = c->rcv.nxt;
-
// 1. Drop invalid packets.
// 1a. Drop packets that should not happen in our current state.
break;
}
- // 1b. Drop packets with a sequence number not in our receive window.
+ // 1b. Discard data that is not in our receive window.
- bool acceptable;
+ if(is_reliable(c)) {
+ bool acceptable;
- if(c->state == SYN_SENT) {
- acceptable = true;
- } else if(len == 0) {
- acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0;
- } else {
- int32_t rcv_offset = seqdiff(hdr.seq, c->rcv.nxt);
+ if(c->state == SYN_SENT) {
+ acceptable = true;
+ } else if(len == 0) {
+ acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0;
+ } 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;
+ // cut already accepted front overlapping
+ if(rcv_offset < 0) {
+ acceptable = len > (size_t) - rcv_offset;
- if(acceptable) {
- ptr -= rcv_offset;
- len += rcv_offset;
- hdr.seq -= rcv_offset;
+ if(acceptable) {
+ ptr -= rcv_offset;
+ len += rcv_offset;
+ hdr.seq -= rcv_offset;
+ }
+ } else {
+ acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt) + len <= c->rcvbuf.maxsize;
}
- } else {
- acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt) + len <= c->rcvbuf.maxsize;
}
- }
- 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);
+ if(!acceptable) {
+ debug(c, "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) {
- return 0;
+ // Ignore unacceptable RST packets.
+ if(hdr.ctl & RST) {
+ return 0;
+ }
+
+ // Otherwise, continue processing.
+ len = 0;
}
+ } else {
+#if UTCP_DEBUG
+ int32_t rcv_offset = seqdiff(hdr.seq, c->rcv.nxt);
- // Otherwise, continue processing.
- len = 0;
+ if(rcv_offset) {
+ debug(c, "packet out of order, offset %u bytes", rcv_offset);
+ }
+
+#endif
}
c->snd.wnd = hdr.wnd; // TODO: move below
// ackno should not roll back, and it should also not be bigger than what we ever could have sent
// (= snd.una + c->sndbuf.used).
+ if(!is_reliable(c)) {
+ if(hdr.ack != c->snd.last && c->state >= ESTABLISHED) {
+ hdr.ack = c->snd.una;
+ }
+ }
+
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);
+ debug(c, "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) {
c->recv(c, NULL, 0);
}
+ if(c->poll && !c->reapable) {
+ c->poll(c, 0);
+ }
+
return 0;
case SYN_RECEIVED:
c->recv(c, NULL, 0);
}
+ if(c->poll && !c->reapable) {
+ c->poll(c, 0);
+ }
+
return 0;
case CLOSING:
// 3. Advance snd.una
advanced = seqdiff(hdr.ack, c->snd.una);
- prevrcvnxt = c->rcv.nxt;
if(advanced) {
// RTT measurement
if(c->rtt_start.tv_sec) {
if(c->rtt_seq == hdr.ack) {
- struct timeval now, diff;
- gettimeofday(&now, NULL);
- timersub(&now, &c->rtt_start, &diff);
- update_rtt(c, diff.tv_sec * 1000000 + diff.tv_usec);
+ struct timespec now;
+ clock_gettime(UTCP_CLOCK, &now);
+ int32_t diff = timespec_diff_usec(&now, &c->rtt_start);
+ update_rtt(c, diff);
c->rtt_start.tv_sec = 0;
} else if(c->rtt_seq < hdr.ack) {
- debug("Cancelling RTT measurement: %u < %u\n", c->rtt_seq, hdr.ack);
+ debug(c, "cancelling RTT measurement: %u < %u\n", c->rtt_seq, hdr.ack);
c->rtt_start.tv_sec = 0;
}
}
assert(data_acked >= 0);
+#ifndef NDEBUG
int32_t bufused = seqdiff(c->snd.last, c->snd.una);
assert(data_acked <= bufused);
+#endif
if(data_acked) {
- buffer_get(&c->sndbuf, NULL, data_acked);
+ buffer_discard(&c->sndbuf, data_acked);
+
+ if(is_reliable(c)) {
+ c->do_poll = true;
+ }
}
// Also advance snd.nxt if possible
c->snd.una = hdr.ack;
- c->dupack = 0;
- c->snd.cwnd += utcp->mtu;
+ if(c->dupack) {
+ if(c->dupack >= 3) {
+ debug(c, "fast recovery ended\n");
+ c->snd.cwnd = c->snd.ssthresh;
+ }
+
+ c->dupack = 0;
+ }
+
+ // Increase the congestion window according to RFC 5681
+ if(c->snd.cwnd < c->snd.ssthresh) {
+ c->snd.cwnd += min(advanced, utcp->mss); // eq. 2
+ } else {
+ c->snd.cwnd += max(1, (utcp->mss * utcp->mss) / c->snd.cwnd); // eq. 3
+ }
if(c->snd.cwnd > c->sndbuf.maxsize) {
c->snd.cwnd = c->sndbuf.maxsize;
}
+ debug_cwnd(c);
+
// Check if we have sent a FIN that is now ACKed.
switch(c->state) {
case FIN_WAIT_1:
case CLOSING:
if(c->snd.una == c->snd.last) {
- gettimeofday(&c->conn_timeout, NULL);
- c->conn_timeout.tv_sec += 60;
+ clock_gettime(UTCP_CLOCK, &c->conn_timeout);
+ c->conn_timeout.tv_sec += utcp->timeout;
set_state(c, TIME_WAIT);
}
break;
}
} else {
- if(!len && is_reliable(c)) {
+ if(!len && is_reliable(c) && c->snd.una != c->snd.last) {
c->dupack++;
+ debug(c, "duplicate ACK %d\n", c->dupack);
if(c->dupack == 3) {
- debug("Triplicate ACK\n");
- //TODO: Resend one packet and go to fast recovery mode. See RFC 6582.
- //We do a very simple variant here; reset the nxt pointer to the last acknowledged packet from the peer.
- //Reset the congestion window so we wait for ACKs.
- c->snd.nxt = c->snd.una;
- c->snd.cwnd = utcp->mtu;
- start_retransmit_timer(c);
+ // RFC 5681 fast recovery
+ debug(c, "fast recovery started\n", c->dupack);
+ uint32_t flightsize = seqdiff(c->snd.nxt, c->snd.una);
+ c->snd.ssthresh = max(flightsize / 2, utcp->mss * 2); // eq. 4
+ c->snd.cwnd = min(c->snd.ssthresh + 3 * utcp->mss, c->sndbuf.maxsize);
+
+ if(c->snd.cwnd > c->sndbuf.maxsize) {
+ c->snd.cwnd = c->sndbuf.maxsize;
+ }
+
+ debug_cwnd(c);
+
+ fast_retransmit(c);
+ } else if(c->dupack > 3) {
+ c->snd.cwnd += utcp->mss;
+
+ if(c->snd.cwnd > c->sndbuf.maxsize) {
+ c->snd.cwnd = c->sndbuf.maxsize;
+ }
+
+ debug_cwnd(c);
}
+
+ // We got an ACK which indicates the other side did get one of our packets.
+ // Reset the retransmission timer to avoid going to slow start,
+ // but don't touch the connection timeout.
+ start_retransmit_timer(c);
}
}
// 4. Update timers
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) {
stop_retransmit_timer(c);
+ timespec_clear(&c->conn_timeout);
} else if(is_reliable(c)) {
start_retransmit_timer(c);
+ clock_gettime(UTCP_CLOCK, &c->conn_timeout);
+ c->conn_timeout.tv_sec += utcp->timeout;
}
}
}
c->rcv.irs = hdr.seq;
- c->rcv.nxt = hdr.seq;
+ c->rcv.nxt = hdr.seq + 1;
+
if(c->shut_wr) {
c->snd.last++;
set_state(c, FIN_WAIT_1);
} else {
set_state(c, ESTABLISHED);
}
- // TODO: notify application of this somehow.
+
break;
case SYN_RECEIVED:
+ // This is a retransmit of a SYN, send back the SYNACK.
+ goto synack;
+
case ESTABLISHED:
case FIN_WAIT_1:
case FIN_WAIT_2:
case CLOSING:
case LAST_ACK:
case TIME_WAIT:
- // Ehm, no. We should never receive a second SYN.
- return 0;
+ // This could be a retransmission. Ignore the SYN flag, but send an ACK back.
+ break;
default:
#ifdef UTCP_DEBUG
#endif
return 0;
}
-
- // SYN counts as one sequence number
- c->rcv.nxt++;
}
// 6. Process new data
return 0;
}
- handle_incoming_data(c, hdr.seq, ptr, len);
+ handle_incoming_data(c, &hdr, ptr, len);
}
// 7. Process FIN stuff
- if((hdr.ctl & FIN) && hdr.seq + len == c->rcv.nxt) {
+ if((hdr.ctl & FIN) && (!is_reliable(c) || hdr.seq + len == c->rcv.nxt)) {
switch(c->state) {
case SYN_SENT:
case SYN_RECEIVED:
break;
case FIN_WAIT_2:
- gettimeofday(&c->conn_timeout, NULL);
- c->conn_timeout.tv_sec += 60;
+ clock_gettime(UTCP_CLOCK, &c->conn_timeout);
+ c->conn_timeout.tv_sec += utcp->timeout;
set_state(c, TIME_WAIT);
break;
c->rcv.nxt++;
len++;
- // Inform the application that the peer closed the connection.
+ // Inform the application that the peer closed its end of the connection.
if(c->recv) {
errno = 0;
c->recv(c, NULL, 0);
}
// Now we send something back if:
- // - we advanced rcv.nxt (ie, we got some data that needs to be ACKed)
+ // - we received data, so we have to send back an ACK
// -> sendatleastone = true
// - or we got an ack, so we should maybe send a bit more data
// -> sendatleastone = false
- ack(c, len || prevrcvnxt != c->rcv.nxt);
+ if(is_reliable(c) || hdr.ctl & SYN || hdr.ctl & FIN) {
+ ack(c, has_data);
+ }
+
return 0;
reset:
hdr.ctl = RST | ACK;
}
- print_packet(utcp, "send", &hdr, sizeof(hdr));
+ print_packet(c, "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);
+ debug(c, "shutdown %d at %u\n", dir, c ? c->snd.last : 0);
if(!c) {
errno = EFAULT;
}
if(c->reapable) {
- debug("Error: shutdown() called on closed connection %p\n", c);
+ debug(c, "shutdown() called on closed connection\n");
errno = EBADF;
return -1;
}
}
// Only process shutting down writes once.
- if (c->shut_wr)
+ if(c->shut_wr) {
return 0;
+ }
c->shut_wr = true;
ack(c, false);
- if(!timerisset(&c->rtrx_timeout)) {
+ if(!timespec_isset(&c->rtrx_timeout)) {
start_retransmit_timer(c);
}
return 0;
}
-int utcp_close(struct utcp_connection *c) {
- if(utcp_shutdown(c, SHUT_RDWR) && errno != ENOTCONN) {
- return -1;
- }
-
- c->recv = NULL;
- c->poll = NULL;
- c->reapable = true;
- return 0;
-}
-
-int utcp_abort(struct utcp_connection *c) {
+static bool reset_connection(struct utcp_connection *c) {
if(!c) {
errno = EFAULT;
- return -1;
+ return false;
}
if(c->reapable) {
- debug("Error: abort() called on closed connection %p\n", c);
+ debug(c, "abort() called on closed connection\n");
errno = EBADF;
- return -1;
+ return false;
}
c->recv = NULL;
c->poll = NULL;
- c->reapable = true;
switch(c->state) {
case CLOSED:
- return 0;
+ return true;
case LISTEN:
case SYN_SENT:
case LAST_ACK:
case TIME_WAIT:
set_state(c, CLOSED);
- return 0;
+ return true;
case SYN_RECEIVED:
case ESTABLISHED:
hdr.wnd = 0;
hdr.ctl = RST;
- print_packet(c->utcp, "send", &hdr, sizeof(hdr));
+ print_packet(c, "send", &hdr, sizeof(hdr));
c->utcp->send(c->utcp, &hdr, sizeof(hdr));
+ return true;
+}
+
+// Closes all the opened connections
+void utcp_abort_all_connections(struct utcp *utcp) {
+ if(!utcp) {
+ errno = EINVAL;
+ return;
+ }
+
+ for(int i = 0; i < utcp->nconnections; i++) {
+ struct utcp_connection *c = utcp->connections[i];
+
+ if(c->reapable || c->state == CLOSED) {
+ continue;
+ }
+
+ utcp_recv_t old_recv = c->recv;
+ utcp_poll_t old_poll = c->poll;
+
+ reset_connection(c);
+
+ if(old_recv) {
+ errno = 0;
+ old_recv(c, NULL, 0);
+ }
+
+ if(old_poll && !c->reapable) {
+ errno = 0;
+ old_poll(c, 0);
+ }
+ }
+
+ return;
+}
+
+int utcp_close(struct utcp_connection *c) {
+ if(utcp_shutdown(c, SHUT_RDWR) && errno != ENOTCONN) {
+ return -1;
+ }
+
+ c->recv = NULL;
+ c->poll = NULL;
+ c->reapable = true;
+ return 0;
+}
+
+int utcp_abort(struct utcp_connection *c) {
+ if(!reset_connection(c)) {
+ return -1;
+ }
+
+ c->reapable = true;
return 0;
}
* The return value is the time to the next timeout in milliseconds,
* or maybe a negative value if the timeout is infinite.
*/
-struct timeval utcp_timeout(struct utcp *utcp) {
- struct timeval now;
- gettimeofday(&now, NULL);
- struct timeval next = {now.tv_sec + 3600, now.tv_usec};
+struct timespec utcp_timeout(struct utcp *utcp) {
+ struct timespec now;
+ clock_gettime(UTCP_CLOCK, &now);
+ struct timespec next = {now.tv_sec + 3600, now.tv_nsec};
for(int i = 0; i < utcp->nconnections; i++) {
struct utcp_connection *c = utcp->connections[i];
// delete connections that have been utcp_close()d.
if(c->state == CLOSED) {
if(c->reapable) {
- debug("Reaping %p\n", c);
+ debug(c, "reaping\n");
free_connection(c);
i--;
}
continue;
}
- if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &now, <)) {
+ if(timespec_isset(&c->conn_timeout) && timespec_lt(&c->conn_timeout, &now)) {
errno = ETIMEDOUT;
c->state = CLOSED;
c->recv(c, NULL, 0);
}
+ if(c->poll && !c->reapable) {
+ c->poll(c, 0);
+ }
+
continue;
}
- if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &now, <)) {
- debug("retransmit()\n");
+ if(timespec_isset(&c->rtrx_timeout) && timespec_lt(&c->rtrx_timeout, &now)) {
+ debug(c, "retransmitting after timeout\n");
retransmit(c);
}
if(c->poll) {
- if((c->state == ESTABLISHED || c->state == CLOSE_WAIT)) {
- uint32_t len = buffer_free(&c->sndbuf);
+ if((c->state == ESTABLISHED || c->state == CLOSE_WAIT) && c->do_poll) {
+ c->do_poll = false;
+ uint32_t len = buffer_free(&c->sndbuf);
if(len) {
c->poll(c, len);
}
}
- if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <)) {
+ if(timespec_isset(&c->conn_timeout) && timespec_lt(&c->conn_timeout, &next)) {
next = c->conn_timeout;
}
- if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &next, <)) {
+ if(timespec_isset(&c->rtrx_timeout) && timespec_lt(&c->rtrx_timeout, &next)) {
next = c->rtrx_timeout;
}
}
- struct timeval diff;
+ struct timespec diff;
- timersub(&next, &now, &diff);
+ timespec_sub(&next, &now, &diff);
return diff;
}
return NULL;
}
+ utcp_set_mtu(utcp, DEFAULT_MTU);
+
+ if(!utcp->pkt) {
+ free(utcp);
+ return NULL;
+ }
+
+ if(!CLOCK_GRANULARITY) {
+ struct timespec res;
+ clock_getres(UTCP_CLOCK, &res);
+ CLOCK_GRANULARITY = res.tv_sec * USEC_PER_SEC + res.tv_nsec / 1000;
+ }
+
utcp->accept = accept;
utcp->pre_accept = pre_accept;
utcp->send = send;
utcp->priv = priv;
- utcp->mtu = DEFAULT_MTU;
utcp->timeout = DEFAULT_USER_TIMEOUT; // sec
- utcp->rto = START_RTO; // usec
return utcp;
}
for(int i = 0; i < utcp->nconnections; i++) {
struct utcp_connection *c = utcp->connections[i];
- if(!c->reapable)
+ if(!c->reapable) {
if(c->recv) {
c->recv(c, NULL, 0);
}
+ if(c->poll && !c->reapable) {
+ c->poll(c, 0);
+ }
+ }
+
buffer_exit(&c->rcvbuf);
buffer_exit(&c->sndbuf);
free(c);
}
free(utcp->connections);
+ free(utcp->pkt);
free(utcp);
}
return utcp ? utcp->mtu : 0;
}
+uint16_t utcp_get_mss(struct utcp *utcp) {
+ return utcp ? utcp->mss : 0;
+}
+
void utcp_set_mtu(struct utcp *utcp, uint16_t mtu) {
- // TODO: handle overhead of the header
- if(utcp) {
- utcp->mtu = mtu;
+ if(!utcp) {
+ return;
+ }
+
+ if(mtu <= sizeof(struct hdr)) {
+ return;
+ }
+
+ if(mtu > utcp->mtu) {
+ char *new = realloc(utcp->pkt, mtu + sizeof(struct hdr));
+
+ if(!new) {
+ return;
+ }
+
+ utcp->pkt = new;
}
+
+ utcp->mtu = mtu;
+ utcp->mss = mtu - sizeof(struct hdr);
}
void utcp_reset_timers(struct utcp *utcp) {
return;
}
- struct timeval now, then;
+ struct timespec now, then;
- gettimeofday(&now, NULL);
+ clock_gettime(UTCP_CLOCK, &now);
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;
- }
+ struct utcp_connection *c = utcp->connections[i];
+
+ if(c->reapable) {
+ continue;
+ }
+
+ if(timespec_isset(&c->rtrx_timeout)) {
+ c->rtrx_timeout = now;
+ }
+
+ if(timespec_isset(&c->conn_timeout)) {
+ c->conn_timeout = then;
+ }
+
+ c->rtt_start.tv_sec = 0;
- if(utcp->rto > START_RTO) {
- utcp->rto = START_RTO;
+ if(c->rto > START_RTO) {
+ c->rto = START_RTO;
+ }
}
}
}
size_t utcp_get_sndbuf_free(struct utcp_connection *c) {
- if (!c)
+ if(!c) {
return 0;
+ }
switch(c->state) {
case SYN_SENT:
if(c->sndbuf.maxsize != size) {
c->sndbuf.maxsize = -1;
}
+
+ c->do_poll = is_reliable(c) && buffer_free(&c->sndbuf);
}
size_t utcp_get_rcvbuf(struct utcp_connection *c) {
}
}
+size_t utcp_get_sendq(struct utcp_connection *c) {
+ return c->sndbuf.used;
+}
+
+size_t utcp_get_recvq(struct utcp_connection *c) {
+ return c->rcvbuf.used;
+}
+
bool utcp_get_nodelay(struct utcp_connection *c) {
return c ? c->nodelay : false;
}
void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
if(c) {
c->poll = poll;
+ c->do_poll = is_reliable(c) && buffer_free(&c->sndbuf);
}
}
utcp->pre_accept = pre_accept;
}
}
+
+void utcp_expect_data(struct utcp_connection *c, bool expect) {
+ if(!c || c->reapable) {
+ return;
+ }
+
+ if(!(c->state == ESTABLISHED || c->state == FIN_WAIT_1 || c->state == FIN_WAIT_2)) {
+ return;
+ }
+
+ if(expect) {
+ // If we expect data, start the connection timer.
+ if(!timespec_isset(&c->conn_timeout)) {
+ clock_gettime(UTCP_CLOCK, &c->conn_timeout);
+ c->conn_timeout.tv_sec += c->utcp->timeout;
+ }
+ } else {
+ // If we want to cancel expecting data, only clear the timer when there is no unACKed data.
+ if(c->snd.una == c->snd.last) {
+ timespec_clear(&c->conn_timeout);
+ }
+ }
+}
+
+void utcp_offline(struct utcp *utcp, bool offline) {
+ struct timespec now;
+ clock_gettime(UTCP_CLOCK, &now);
+
+ for(int i = 0; i < utcp->nconnections; i++) {
+ struct utcp_connection *c = utcp->connections[i];
+
+ if(c->reapable) {
+ continue;
+ }
+
+ utcp_expect_data(c, offline);
+
+ if(!offline) {
+ if(timespec_isset(&c->rtrx_timeout)) {
+ c->rtrx_timeout = now;
+ }
+
+ utcp->connections[i]->rtt_start.tv_sec = 0;
+
+ if(c->rto > START_RTO) {
+ c->rto = START_RTO;
+ }
+ }
+ }
+}
+
+void utcp_set_retransmit_cb(struct utcp *utcp, utcp_retransmit_t retransmit) {
+ utcp->retransmit = retransmit;
+}
+
+void utcp_set_clock_granularity(long granularity) {
+ CLOCK_GRANULARITY = granularity;
+}
projects / utcp / blobdiff