From c93ef1391476090d5afacb899632df5476f964ed Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Fri, 25 Jul 2014 13:18:58 +0200 Subject: [PATCH] Do port numbers properly. - Outgoing connections automatically get a port number >= 32768 assigned. - *connect() and *accept() get a port number as argument. - Connections are now stored in a sorted array with O(log(N)) lookup time. --- UTCP | 2 - selftest.c | 16 ++-- test.c | 4 +- utcp.c | 219 +++++++++++++++++++++++++++++++++++------------------ utcp.h | 12 +-- 5 files changed, 161 insertions(+), 92 deletions(-) diff --git a/UTCP b/UTCP index 02496cc..f7b66ba 100644 --- a/UTCP +++ b/UTCP @@ -15,11 +15,9 @@ DIFFERENCES FROM RFC 793: * No checksum. UTCP requires the application to handle packet integrity. * 32-bit window size. Big window sizes are the default. * No ECN, PSH, URG -* Ports are a bit strange (for now). TODO v1.0: -* Do ports the same way as real TCP? * Implement send buffer * Window scaling * Handle retransmission diff --git a/selftest.c b/selftest.c index c1df40f..dae05bf 100644 --- a/selftest.c +++ b/selftest.c @@ -31,14 +31,14 @@ int do_recv(struct utcp_connection *x, void *data, size_t len) { return 0; } -bool do_pre_accept(struct utcp *utcp, void *data, size_t len) { +bool do_pre_accept(struct utcp *utcp, uint16_t port) { fprintf(stderr, "pre-accept\n"); - if(len != 2 || strncmp(data, "oi", 2)) + if(port != 7) return false; return true; } -void do_accept(struct utcp_connection *c, void *data, size_t len) { +void do_accept(struct utcp_connection *c, uint16_t port) { fprintf(stderr, "accept\n"); utcp_accept(c, do_recv, NULL); } @@ -64,24 +64,24 @@ int main(int argc, char *argv[]) { b = utcp_init(NULL, NULL, do_send, NULL); fprintf(stderr, "Testing connection to closed port\n\n"); - c = utcp_connect(b, "zomg", 4, do_recv, NULL); + c = utcp_connect(b, 6, do_recv, NULL); fprintf(stderr, "\nTesting conection to non-listening side\n\n"); - c = utcp_connect(a, "oi", 2, do_recv, NULL); + c = utcp_connect(a, 7, do_recv, NULL); fprintf(stderr, "\nTesting connection to open port, close\n\n"); - c = utcp_connect(b, "oi", 2, do_recv, NULL); + c = utcp_connect(b, 7, do_recv, NULL); fprintf(stderr, "closing...\n"); utcp_close(c); fprintf(stderr, "\nTesting connection to open port, abort\n\n"); - c = utcp_connect(b, "oi", 2, do_recv, NULL); + c = utcp_connect(b, 7, do_recv, NULL); fprintf(stderr, "aborting...\n"); utcp_abort(c); fprintf(stderr, "\nTesting connection with data transfer\n\n"); - c = utcp_connect(b, "oi", 2, do_recv, NULL); + c = utcp_connect(b, 7, do_recv, NULL); utcp_send(c, "Hello world!\n", 13); utcp_send(c, "This is a test.\n", 16); fprintf(stderr, "closing...\n"); diff --git a/test.c b/test.c index 0e0cb2e..956d1ef 100644 --- a/test.c +++ b/test.c @@ -30,7 +30,7 @@ int do_recv(struct utcp_connection *c, void *data, size_t len) { return write(0, data, len); } -void do_accept(struct utcp_connection *nc, void *data, size_t len) { +void do_accept(struct utcp_connection *nc, uint16_t port) { utcp_accept(nc, do_recv, NULL); c = nc; } @@ -77,7 +77,7 @@ int main(int argc, char *argv[]) { return 1; if(!server) - c = utcp_connect(u, "test", 4, do_recv, NULL); + c = utcp_connect(u, 1, do_recv, NULL); struct pollfd fds[2] = { {.fd = 0, .events = POLLIN | POLLERR | POLLHUP}, diff --git a/utcp.c b/utcp.c index 5db93ea..e6f70f7 100644 --- a/utcp.c +++ b/utcp.c @@ -109,6 +109,9 @@ struct utcp_connection { struct timeval conn_timeout; struct timeval rtrx_timeout; + + char *sndbuf; + uint32_t sndbufsize; }; struct utcp { @@ -160,96 +163,127 @@ static void print_packet(void *pkt, size_t len) { fprintf(stderr, "\n"); } -static struct utcp_connection *allocate_connection(struct utcp *utcp) { - struct utcp_connection *c; +static void list_connections(struct utcp *utcp) { + fprintf(stderr, "%p has %d connections:\n", utcp, utcp->nconnections); + for(int i = 0; i < utcp->nconnections; i++) + fprintf(stderr, " %u -> %u state %s\n", utcp->connections[i]->src, utcp->connections[i]->dst, strstate[utcp->connections[i]->state]); +} - // Initial allocation? +// Connections are stored in a sorted list. +// This gives O(log(N)) lookup time, O(N log(N)) insertion time and O(N) deletion time. - if(!utcp->nconnections) { - utcp->nallocated = 4; - utcp->nconnections = 1; // Skip 0 - utcp->connections = calloc(utcp->nallocated, sizeof *utcp->connections); - } +static int compare(const void *va, const void *vb) { + const struct utcp_connection *a = *(struct utcp_connection **)va; + const struct utcp_connection *b = *(struct utcp_connection **)vb; + if(!a->src || !b->src) + abort(); + int c = (int)a->src - (int)b->src; + if(c) + return c; + c = (int)a->dst - (int)b->dst; + return c; +} - // If there is a hole in the list of connections, use it. - // Otherwise, add a new connection to the end. +static struct utcp_connection *find_connection(const struct utcp *utcp, uint16_t src, uint16_t dst) { + if(!utcp->nconnections) + return NULL; + struct utcp_connection key = { + .src = src, + .dst = dst, + }, *keyp = &key; + struct utcp_connection **match = bsearch(&keyp, utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare); + return match ? *match : NULL; +} - if(utcp->gap >= 0) { - c = utcp->connections[utcp->gap] = calloc(1, sizeof *c); - c->src = utcp->gap; - while(++utcp->gap < utcp->nconnections) - if(!utcp->connections[utcp->gap]) - break; +static void free_connection(struct utcp_connection *c) { + struct utcp *utcp = c->utcp; + struct utcp_connection **cp = bsearch(&c, utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare); + if(!cp) + abort(); - if(utcp->gap >= utcp->nconnections) - utcp->gap = -1; - } else { - // Too many connections? + int i = cp - utcp->connections; + memmove(cp + i, cp + i + 1, (utcp->nconnections - i - 1) * sizeof *cp); + utcp->nconnections--; - if(utcp->nconnections >= 65536) { + free(c); +} + +static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t src, uint16_t dst) { + // Check whether this combination of src and dst is free + + if(src) { + if(find_connection(utcp, src, dst)) { + errno = EADDRINUSE; + return NULL; + } + } else { // If src == 0, generate a random port number with the high bit set + if(utcp->nconnections >= 32767) { errno = ENOMEM; return NULL; } + src = rand() | 0x8000; + while(find_connection(utcp, src, dst)) + src++; + } - // Need to reserve more memory? + // Allocate memory for the new connection - if(utcp->nconnections >= utcp->nallocated) { + if(utcp->nconnections >= utcp->nallocated) { + if(!utcp->nallocated) + utcp->nallocated = 4; + else utcp->nallocated *= 2; - utcp->connections = realloc(utcp->connections, utcp->nallocated * sizeof *utcp->connections); + struct utcp_connection **new_array = realloc(utcp->connections, utcp->nallocated * sizeof *utcp->connections); + if(!new_array) { + errno = ENOMEM; + return NULL; } + utcp->connections = new_array; + } - c = utcp->connections[utcp->nconnections] = calloc(1, sizeof *c); - c->src = utcp->nconnections++; + struct utcp_connection *c = calloc(1, sizeof *c); + if(!c) { + errno = ENOMEM; + return NULL; } + // Fill in the details + + c->src = src; + c->dst = dst; c->snd.iss = rand(); c->snd.una = c->snd.iss; c->snd.nxt = c->snd.iss + 1; c->rcv.wnd = utcp->mtu; c->utcp = utcp; - return c; -} -static struct utcp_connection *find_connection(struct utcp *utcp, uint16_t src) { - if(src < utcp->nconnections && utcp->connections[src]) - return utcp->connections[src]; + // Add it to the sorted list of connections - errno = EINVAL; - return NULL; -} + utcp->connections[utcp->nconnections++] = c; + qsort(utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare); -static void free_connection(struct utcp_connection *c) { - if(!c) - return; - if(c->utcp->gap < 0 || c->src < c->utcp->gap) - c->utcp->gap = c->src; - c->utcp->connections[c->src] = NULL; - free(c); + return c; } -struct utcp_connection *utcp_connect(struct utcp *utcp, void *data, size_t len, utcp_recv_t recv, void *priv) { - struct utcp_connection *c = allocate_connection(utcp); +struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv) { + struct utcp_connection *c = allocate_connection(utcp, 0, dst); if(!c) return NULL; c->recv = recv; - struct { - struct hdr hdr; - char data[len]; - } pkt; + struct hdr hdr; - pkt.hdr.src = c->src; - pkt.hdr.dst = 0; - pkt.hdr.seq = c->snd.iss; - pkt.hdr.ack = 0; - pkt.hdr.ctl = SYN; - pkt.hdr.wnd = c->rcv.wnd; - memcpy(pkt.data, data, len); + hdr.src = c->src; + hdr.dst = c->dst; + hdr.seq = c->snd.iss; + hdr.ack = 0; + hdr.ctl = SYN; + hdr.wnd = c->rcv.wnd; set_state(c, SYN_SENT); - utcp->send(utcp, &pkt, sizeof pkt.hdr + len); + utcp->send(utcp, &hdr, sizeof hdr); // Set timeout? @@ -295,6 +329,15 @@ int utcp_send(struct utcp_connection *c, void *data, size_t len) { errno = EPIPE; return -1; } + + if(!len) + return 0; + + if(!data) { + errno = EFAULT; + return -1; + } + struct { struct hdr hdr; @@ -328,6 +371,19 @@ static void swap_ports(struct hdr *hdr) { } int utcp_recv(struct utcp *utcp, void *data, size_t len) { + if(!utcp) { + errno = EFAULT; + return -1; + } + + if(!len) + return 0; + + if(!data) { + errno = EFAULT; + return -1; + } + fprintf(stderr, "%p got: ", utcp); print_packet(data, len); @@ -346,7 +402,9 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) { return -1; } - struct utcp_connection *c = find_connection(utcp, hdr.dst); + //list_connections(utcp); + + struct utcp_connection *c = find_connection(utcp, hdr.dst, hdr.src); // Is it for a new connection? @@ -354,17 +412,14 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) { if(hdr.ctl & RST) return 0; - if(hdr.ctl & SYN && !(hdr.ctl & ACK) && utcp->accept && (!utcp->pre_accept || utcp->pre_accept(utcp, data, len)) && (c = allocate_connection(utcp))) { // LISTEN + if(hdr.ctl & SYN && !(hdr.ctl & ACK) && utcp->accept && (!utcp->pre_accept || utcp->pre_accept(utcp, hdr.dst)) && (c = allocate_connection(utcp, hdr.dst, hdr.src))) { // LISTEN // Return SYN+ACK c->snd.wnd = hdr.wnd; c->rcv.irs = hdr.seq; - c->snd.iss = rand(); - c->snd.una = c->snd.iss; - c->snd.nxt = c->snd.iss + 1; c->rcv.nxt = c->rcv.irs + 1; set_state(c, SYN_RECEIVED); - hdr.dst = c->dst = hdr.src; + hdr.dst = c->dst; hdr.src = c->src; hdr.ack = c->rcv.irs + 1; hdr.seq = c->snd.iss; @@ -509,7 +564,7 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) { switch(c->state) { case SYN_RECEIVED: if(hdr.ack >= c->snd.una && hdr.ack <= c->snd.nxt) - c->utcp->accept(c, NULL, 0); + c->utcp->accept(c, hdr.dst); if(c->state != ESTABLISHED) goto reset; @@ -636,21 +691,27 @@ ack_and_drop: return 0; } -void utcp_shutdown(struct utcp_connection *c, int dir) { +int utcp_shutdown(struct utcp_connection *c, int dir) { + if(!c) { + errno = EFAULT; + return -1; + } + if(c->reapable) { fprintf(stderr, "Error: shutdown() called on closed connection %p\n", c); - return; + errno = EBADF; + return -1; } // TODO: handle dir switch(c->state) { case CLOSED: - return; + return 0; case LISTEN: case SYN_SENT: set_state(c, CLOSED); - return; + return 0; case SYN_RECEIVED: case ESTABLISHED: @@ -658,7 +719,7 @@ void utcp_shutdown(struct utcp_connection *c, int dir) { break; case FIN_WAIT_1: case FIN_WAIT_2: - return; + return 0; case CLOSE_WAIT: set_state(c, LAST_ACK); break; @@ -666,7 +727,7 @@ void utcp_shutdown(struct utcp_connection *c, int dir) { case CLOSING: case LAST_ACK: case TIME_WAIT: - return; + return 0; } // Send FIN @@ -683,31 +744,40 @@ void utcp_shutdown(struct utcp_connection *c, int dir) { c->snd.nxt += 1; c->utcp->send(c->utcp, &hdr, sizeof hdr); + return 0; } -void utcp_close(struct utcp_connection *c) { - utcp_shutdown(c, SHUT_RDWR); +int utcp_close(struct utcp_connection *c) { + if(utcp_shutdown(c, SHUT_RDWR)) + return -1; c->reapable = true; + return 0; } -void utcp_abort(struct utcp_connection *c) { +int utcp_abort(struct utcp_connection *c) { + if(!c) { + errno = EFAULT; + return -1; + } + if(c->reapable) { fprintf(stderr, "Error: abort() called on closed connection %p\n", c); - return; + errno = EBADF; + return -1; } c->reapable = true; switch(c->state) { case CLOSED: - return; + return 0; case LISTEN: case SYN_SENT: case CLOSING: case LAST_ACK: case TIME_WAIT: set_state(c, CLOSED); - return; + return 0; case SYN_RECEIVED: case ESTABLISHED: @@ -730,6 +800,7 @@ void utcp_abort(struct utcp_connection *c) { hdr.ctl = RST; c->utcp->send(c->utcp, &hdr, sizeof hdr); + return 0; } void utcp_timeout(struct utcp *utcp) { diff --git a/utcp.h b/utcp.h index a404b43..45cb6f3 100644 --- a/utcp.h +++ b/utcp.h @@ -38,21 +38,21 @@ struct utcp; struct utcp_connection; #endif -typedef bool (*utcp_pre_accept_t)(struct utcp *utcp, void *data, size_t len); -typedef void (*utcp_accept_t)(struct utcp_connection *utcp_connection, void *data, size_t len); +typedef bool (*utcp_pre_accept_t)(struct utcp *utcp, uint16_t port); +typedef void (*utcp_accept_t)(struct utcp_connection *utcp_connection, uint16_t port); typedef int (*utcp_send_t)(struct utcp *utcp, void *data, size_t len); typedef int (*utcp_recv_t)(struct utcp_connection *connection, void *data, size_t len); extern struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv); extern void utcp_exit(struct utcp *utcp); -extern struct utcp_connection *utcp_connect(struct utcp *utcp, void *data, size_t len, utcp_recv_t recv, void *priv); +extern struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t port, utcp_recv_t recv, void *priv); extern void utcp_accept(struct utcp_connection *utcp, utcp_recv_t recv, void *priv); extern int utcp_send(struct utcp_connection *connection, void *data, size_t len); extern int utcp_recv(struct utcp *utcp, void *data, size_t len); -extern void utcp_close(struct utcp_connection *connection); -extern void utcp_abort(struct utcp_connection *connection); -extern void utcp_shutdown(struct utcp_connection *connection, int how); +extern int utcp_close(struct utcp_connection *connection); +extern int utcp_abort(struct utcp_connection *connection); +extern int utcp_shutdown(struct utcp_connection *connection, int how); extern void utcp_timeout(struct utcp *utcp); #endif -- 2.39.2