/**************************************************************************** * net/tcp/tcp_conn.c * * Copyright (C) 2007-2011, 2013-2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Large parts of this file were leveraged from uIP logic: * * Copyright (c) 2001-2003, Adam Dunkels. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) #include #include #include #include #include #include #include #include #include #include #include #include "devif/devif.h" #include "tcp/tcp.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define IPv4 ((struct net_iphdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) #define IPv6 ((struct net_ipv6hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) /**************************************************************************** * Private Data ****************************************************************************/ /* The array containing all uIP TCP connections. */ static struct tcp_conn_s g_tcp_connections[CONFIG_NET_TCP_CONNS]; /* A list of all free TCP connections */ static dq_queue_t g_free_tcp_connections; /* A list of all connected TCP connections */ static dq_queue_t g_active_tcp_connections; /* Last port used by a TCP connection connection. */ static uint16_t g_last_tcp_port; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_listener * * Description: * Given a local port number (in network byte order), find the TCP * connection that listens on this this port. * * Primary uses: (1) to determine if a port number is available, (2) to * To identify the socket that will accept new connections on a local port. * ****************************************************************************/ #ifdef CONFIG_NETDEV_MULTINIC static FAR struct tcp_conn_s *tcp_listener(in_addr_t ipaddr, uint16_t portno) #else static FAR struct tcp_conn_s *tcp_listener(uint16_t portno) #endif { FAR struct tcp_conn_s *conn; int i; /* Check if this port number is in use by any active UIP TCP connection */ for (i = 0; i < CONFIG_NET_TCP_CONNS; i++) { conn = &g_tcp_connections[i]; /* Check if this connection is open and the local port assignment * matches the requested port number. */ if (conn->tcpstateflags != TCP_CLOSED && conn->lport == portno) { #ifdef CONFIG_NETDEV_MULTINIC /* If there are multiple interface devices, then the local IP * address of the connection must also match. INADDR_ANY is a * special case: There can only be instance of a port number * with INADDR_ANY. */ if (net_ipv4addr_cmp(conn->u.ipv4.laddr, ipaddr) || #ifdef CONFIG_NET_IPv6 net_ipv4addr_cmp(conn->u.ipv4.laddr, g_ipv4_allzeroaddr)) #else net_ipv4addr_cmp(conn->u.ipv4.laddr, INADDR_ANY)) #endif #endif { /* The port number is in use, return the connection */ return conn; } } } return NULL; } /**************************************************************************** * Name: tcp_selectport * * Description: * If the port number is zero; select an unused port for the connection. * If the port number is non-zero, verify that no other connection has * been created with this port number. * * Input Parameters: * portno -- the selected port number in host order. Zero means no port * selected. * * Return: * 0 on success, negated errno on failure: * * EADDRINUSE * The given address is already in use. * EADDRNOTAVAIL * Cannot assign requested address (unlikely) * * Assumptions: * Interrupts are disabled * ****************************************************************************/ #ifdef CONFIG_NETDEV_MULTINIC static int tcp_selectport(in_addr_t ipaddr, uint16_t portno) #else static int tcp_selectport(uint16_t portno) #endif { if (portno == 0) { /* No local port assigned. Loop until we find a valid listen port number * that is not being used by any other connection. NOTE the following loop * is assumed to terminate but could not if all 32000-4096+1 ports are * in used (unlikely). */ do { /* Guess that the next available port number will be the one after * the last port number assigned. */ portno = ++g_last_tcp_port; /* Make sure that the port number is within range */ if (g_last_tcp_port >= 32000) { g_last_tcp_port = 4096; } } #ifdef CONFIG_NETDEV_MULTINIC while (tcp_listener(ipaddr, htons(g_last_tcp_port))); #else while (tcp_listener(htons(g_last_tcp_port))); #endif } else { /* A port number has been supplied. Verify that no other TCP/IP * connection is using this local port. */ #ifdef CONFIG_NETDEV_MULTINIC if (tcp_listener(ipaddr, portno)) #else if (tcp_listener(portno)) #endif { /* It is in use... return EADDRINUSE */ return -EADDRINUSE; } } /* Return the selected or verified port number */ return portno; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_initialize * * Description: * Initialize the TCP/IP connection structures. Called only once and only * from the UIP layer at start-up in normal user mode. * ****************************************************************************/ void tcp_initialize(void) { int i; /* Initialize the queues */ dq_init(&g_free_tcp_connections); dq_init(&g_active_tcp_connections); /* Now initialize each connection structure */ for (i = 0; i < CONFIG_NET_TCP_CONNS; i++) { /* Mark the connection closed and move it to the free list */ g_tcp_connections[i].tcpstateflags = TCP_CLOSED; dq_addlast(&g_tcp_connections[i].node, &g_free_tcp_connections); } g_last_tcp_port = 1024; } /**************************************************************************** * Name: tcp_alloc * * Description: * Find a free TCP/IP connection structure and allocate it * for use. This is normally something done by the implementation of the * socket() API but is also called from the interrupt level when a TCP * packet is received while "listening" * ****************************************************************************/ FAR struct tcp_conn_s *tcp_alloc(void) { FAR struct tcp_conn_s *conn; net_lock_t flags; /* Because this routine is called from both interrupt level and * and from user level, we have not option but to disable interrupts * while accessing g_free_tcp_connections[]; */ flags = net_lock(); /* Return the entry from the head of the free list */ conn = (FAR struct tcp_conn_s *)dq_remfirst(&g_free_tcp_connections); #ifndef CONFIG_NET_SOLINGER /* Is the free list empty? */ if (!conn) { /* As a fall-back, check for connection structures which can be stalled. * * Search the active connection list for the oldest connection * that is about to be closed anyway. */ FAR struct tcp_conn_s *tmp = (FAR struct tcp_conn_s *)g_active_tcp_connections.head; while (tmp) { nllvdbg("conn: %p state: %02x\n", tmp, tmp->tcpstateflags); /* Is this connection in a state we can sacrifice. */ /* REVISIT: maybe we could check for SO_LINGER but it's buried * in the socket layer. */ if (tmp->tcpstateflags == TCP_CLOSING || tmp->tcpstateflags == TCP_FIN_WAIT_1 || tmp->tcpstateflags == TCP_FIN_WAIT_2 || tmp->tcpstateflags == TCP_TIME_WAIT || tmp->tcpstateflags == TCP_LAST_ACK) { /* Yes.. Is it the oldest one we have seen so far? */ if (!conn || tmp->timer > conn->timer) { /* Yes.. remember it */ conn = tmp; } } /* Look at the next active connection */ tmp = (FAR struct tcp_conn_s *)tmp->node.flink; } /* Did we find a connection that we can re-use? */ if (conn != NULL) { nlldbg("Closing unestablished connection: %p\n", conn); /* Yes... free it. This will remove the connection from the list * of active connections and release all resources held by the * connection. * * REVISIT: Could there be any higher level, socket interface * that needs to be informed that we did this to them? * * Actually yes. When CONFIG_NET_SOLINGER is enabled there is a * pending callback in netclose_disconnect waiting for getting * woken up. Otherwise there's the callback too, but no one is * waiting for it. */ tcp_free(conn); /* Now there is guaranteed to be one free connection. Get it! */ conn = (FAR struct tcp_conn_s *)dq_remfirst(&g_free_tcp_connections); } } #endif net_unlock(flags); /* Mark the connection allocated */ if (conn) { memset(conn, 0, sizeof(struct tcp_conn_s)); conn->tcpstateflags = TCP_ALLOCATED; } return conn; } /**************************************************************************** * Name: tcp_free * * Description: * Free a connection structure that is no longer in use. This should be * done by the implementation of close() * ****************************************************************************/ void tcp_free(FAR struct tcp_conn_s *conn) { FAR struct devif_callback_s *cb; FAR struct devif_callback_s *next; #ifdef CONFIG_NET_TCP_WRITE_BUFFERS FAR struct tcp_wrbuffer_s *wrbuffer; #endif net_lock_t flags; /* Because g_free_tcp_connections is accessed from user level and interrupt * level, code, it is necessary to keep interrupts disabled during this * operation. */ DEBUGASSERT(conn->crefs == 0); flags = net_lock(); /* Free remaining callbacks, actually there should be only the close callback * left. */ for (cb = conn->list; cb; cb = next) { next = cb->flink; tcp_callback_free(conn, cb); } /* TCP_ALLOCATED means that that the connection is not in the active list * yet. */ if (conn->tcpstateflags != TCP_ALLOCATED) { /* Remove the connection from the active list */ dq_rem(&conn->node, &g_active_tcp_connections); } #ifdef CONFIG_NET_TCP_READAHEAD /* Release any read-ahead buffers attached to the connection */ iob_free_queue(&conn->readahead); #endif #ifdef CONFIG_NET_TCP_WRITE_BUFFERS /* Release any write buffers attached to the connection */ while ((wrbuffer = (struct tcp_wrbuffer_s *)sq_remfirst(&conn->write_q)) != NULL) { tcp_wrbuffer_release(wrbuffer); } while ((wrbuffer = (struct tcp_wrbuffer_s *)sq_remfirst(&conn->unacked_q)) != NULL) { tcp_wrbuffer_release(wrbuffer); } #endif #ifdef CONFIG_NET_TCPBACKLOG /* Remove any backlog attached to this connection */ if (conn->backlog) { tcp_backlogdestroy(conn); } /* If this connection is, itself, backlogged, then remove it from the * parent connection's backlog list. */ if (conn->blparent) { tcp_backlogdelete(conn->blparent, conn); } #endif /* Mark the connection available and put it into the free list */ conn->tcpstateflags = TCP_CLOSED; dq_addlast(&conn->node, &g_free_tcp_connections); net_unlock(flags); } /**************************************************************************** * Name: tcp_active * * Description: * Find a connection structure that is the appropriate * connection to be used with the provided TCP/IP header * * Assumptions: * This function is called from UIP logic at interrupt level * ****************************************************************************/ FAR struct tcp_conn_s *tcp_active(FAR struct net_driver_s *dev, FAR struct tcp_hdr_s *tcp) { FAR struct net_iphdr_s *ip = IPv4; FAR struct tcp_conn_s *conn; in_addr_t srcipaddr; #ifdef CONFIG_NETDEV_MULTINIC in_addr_t destipaddr; #endif conn = (FAR struct tcp_conn_s *)g_active_tcp_connections.head; srcipaddr = net_ip4addr_conv32(ip->srcipaddr); #ifdef CONFIG_NETDEV_MULTINIC destipaddr = net_ip4addr_conv32(ip->destipaddr); #endif while (conn) { /* Find an open connection matching the TCP input. The following * checks are performed: * * - The local port number is checked against the destination port * number in the received packet. * - The remote port number is checked if the connection is bound * to a remote port. * - If multiple network interfaces are supported, then the local * IP address is available and we will insist that the * destination IP matches the bound address. If a socket is * bound to INADDRY_ANY, then it should receive all packets * directed to the port. * - Finally, if the connection is bound to a remote IP address, * the source IP address of the packet is checked. * * If all of the above are true then the newly received TCP packet * is destined for this TCP connection. */ if (conn->tcpstateflags != TCP_CLOSED && tcp->destport == conn->lport && tcp->srcport == conn->rport && #ifdef CONFIG_NETDEV_MULTINIC (net_ipv4addr_cmp(conn->u.ipv4.laddr, g_ipv4_allzeroaddr) || net_ipv4addr_cmp(destipaddr, conn->u.ipv4.laddr)) && #endif net_ipv4addr_cmp(srcipaddr, conn->u.ipv4.raddr)) { /* Matching connection found.. break out of the loop and return a * reference to it. */ break; } /* Look at the next active connection */ conn = (FAR struct tcp_conn_s *)conn->node.flink; } return conn; } /**************************************************************************** * Name: tcp_nextconn * * Description: * Traverse the list of active TCP connections * * Assumptions: * This function is called from UIP logic at interrupt level (or with * interrupts disabled). * ****************************************************************************/ FAR struct tcp_conn_s *tcp_nextconn(FAR struct tcp_conn_s *conn) { if (!conn) { return (FAR struct tcp_conn_s *)g_active_tcp_connections.head; } else { return (FAR struct tcp_conn_s *)conn->node.flink; } } /**************************************************************************** * Name: tcp_alloc_accept * * Description: * Called when driver interrupt processing matches the incoming packet * with a connection in LISTEN. In that case, this function will create * a new connection and initialize it to send a SYNACK in return. * * Assumptions: * This function is called from UIP logic at interrupt level * ****************************************************************************/ FAR struct tcp_conn_s *tcp_alloc_accept(FAR struct net_driver_s *dev, FAR struct tcp_hdr_s *tcp) { FAR struct net_iphdr_s *ip = IPv4; FAR struct tcp_conn_s *conn; conn = tcp_alloc(); if (conn) { /* Fill in the necessary fields for the new connection. */ conn->rto = TCP_RTO; conn->timer = TCP_RTO; conn->sa = 0; conn->sv = 4; conn->nrtx = 0; conn->lport = tcp->destport; conn->rport = tcp->srcport; conn->mss = TCP_IPv4_INITIAL_MSS(dev); net_ipv4addr_copy(conn->u.ipv4.raddr, net_ip4addr_conv32(ip->srcipaddr)); #ifdef CONFIG_NETDEV_MULTINIC net_ipv4addr_copy(conn->u.ipv4.laddr, net_ip4addr_conv32(ip->destipaddr)); #endif conn->tcpstateflags = TCP_SYN_RCVD; tcp_initsequence(conn->sndseq); conn->unacked = 1; #ifdef CONFIG_NET_TCP_WRITE_BUFFERS conn->expired = 0; conn->isn = 0; conn->sent = 0; #endif /* rcvseq should be the seqno from the incoming packet + 1. */ memcpy(conn->rcvseq, tcp->seqno, 4); #ifdef CONFIG_NET_TCP_READAHEAD /* Initialize the list of TCP read-ahead buffers */ IOB_QINIT(&conn->readahead); #endif #ifdef CONFIG_NET_TCP_WRITE_BUFFERS /* Initialize the write buffer lists */ sq_init(&conn->write_q); sq_init(&conn->unacked_q); #endif /* And, finally, put the connection structure into the active list. * Interrupts should already be disabled in this context. */ dq_addlast(&conn->node, &g_active_tcp_connections); } return conn; } /**************************************************************************** * Name: tcp_bind * * Description: * This function implements the lower level parts of the standard TCP * bind() operation. * * Return: * 0 on success or -EADDRINUSE on failure * * Assumptions: * This function is called from normal user level code. * ****************************************************************************/ #ifdef CONFIG_NET_IPv6 int tcp_bind(FAR struct tcp_conn_s *conn, FAR const struct sockaddr_in6 *addr) #else int tcp_bind(FAR struct tcp_conn_s *conn, FAR const struct sockaddr_in *addr) #endif { net_lock_t flags; int port; #ifdef CONFIG_NETDEV_MULTINIC in_addr_t ipaddr; #endif /* Verify or select a local port and address */ flags = net_lock(); #ifdef CONFIG_NETDEV_MULTINIC #ifdef CONFIG_NET_IPv6 /* Get the IPv6 address that we are binding to */ ipaddr = addr->sin6_addr.in6_u.u6_addr16; #else /* Get the IPv4 address that we are binding to */ ipaddr = addr->sin_addr.s_addr; #endif port = tcp_selectport(ipaddr, ntohs(addr->sin_port)); #else /* Verify or select a local port */ port = tcp_selectport(ntohs(addr->sin_port)); #endif net_unlock(flags); if (port < 0) { return port; } /* Save the local address in the connection structure. */ conn->lport = addr->sin_port; #ifdef CONFIG_NETDEV_MULTINIC net_ipv4addr_copy(conn->u.ipv4.laddr, ipaddr); #endif return OK; } /**************************************************************************** * Name: tcp_connect * * Description: * This function implements the lower level parts of the standard * TCP connect() operation: It connects to a remote host using TCP. * * This function is used to start a new connection to the specified * port on the specified host. It uses the connection structure that was * allocated by a preceding socket() call. It sets the connection to * the SYN_SENT state and sets the retransmission timer to 0. This will * cause a TCP SYN segment to be sent out the next time this connection * is periodically processed, which usually is done within 0.5 seconds * after the call to tcp_connect(). * * Assumptions: * This function is called from normal user level code. * ****************************************************************************/ #ifdef CONFIG_NET_IPv6 int tcp_connect(FAR struct tcp_conn_s *conn, FAR const struct sockaddr_in6 *addr) #else int tcp_connect(FAR struct tcp_conn_s *conn, FAR const struct sockaddr_in *addr) #endif { net_lock_t flags; int port; /* The connection is expected to be in the TCP_ALLOCATED state.. i.e., * allocated via up_tcpalloc(), but not yet put into the active connections * list. */ if (!conn || conn->tcpstateflags != TCP_ALLOCATED) { return -EISCONN; } /* If the TCP port has not already been bound to a local port, then select * one now. We assume that the IP address has been bound to a local device, * but the port may still be INPORT_ANY. */ flags = net_lock(); #ifdef CONFIG_NETDEV_MULTINIC port = tcp_selectport(conn->u.ipv4.laddr, ntohs(conn->lport)); #else port = tcp_selectport(ntohs(conn->lport)); #endif net_unlock(flags); if (port < 0) { return port; } /* Initialize and return the connection structure, bind it to the port * number. At this point, we do not know the size of the initial MSS We * know the total size of the packet buffer, but we don't yet know the * size of link layer header. */ conn->tcpstateflags = TCP_SYN_SENT; tcp_initsequence(conn->sndseq); conn->mss = MIN_IPv4_TCP_INITIAL_MSS; conn->unacked = 1; /* TCP length of the SYN is one. */ conn->nrtx = 0; conn->timer = 1; /* Send the SYN next time around. */ conn->rto = TCP_RTO; conn->sa = 0; conn->sv = 16; /* Initial value of the RTT variance. */ conn->lport = htons((uint16_t)port); #ifdef CONFIG_NET_TCP_WRITE_BUFFERS conn->expired = 0; conn->isn = 0; conn->sent = 0; #endif /* The sockaddr port is 16 bits and already in network order */ conn->rport = addr->sin_port; /* The sockaddr address is 32-bits in network order. */ net_ipv4addr_copy(conn->u.ipv4.raddr, addr->sin_addr.s_addr); #ifdef CONFIG_NET_TCP_READAHEAD /* Initialize the list of TCP read-ahead buffers */ IOB_QINIT(&conn->readahead); #endif #ifdef CONFIG_NET_TCP_WRITE_BUFFERS /* Initialize the TCP write buffer lists */ sq_init(&conn->write_q); sq_init(&conn->unacked_q); #endif /* And, finally, put the connection structure into the active * list. Because g_active_tcp_connections is accessed from user level and * interrupt level, code, it is necessary to keep interrupts disabled during * this operation. */ flags = net_lock(); dq_addlast(&conn->node, &g_active_tcp_connections); net_unlock(flags); return OK; } #endif /* CONFIG_NET && CONFIG_NET_TCP */