/**************************************************************************** * net/uip/uip_tcpconn.c * * Copyright (C) 2007-2009 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. * ****************************************************************************/ /**************************************************************************** * Compilation Switches ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) #include #include #include #include #include #include #include #include #include "uip_internal.h" /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /* The array containing all uIP TCP connections. */ static struct uip_conn 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 g_last_tcp_port; /* g_tcp_sequence[] is used to generate TCP sequence numbers */ static uint8 g_tcp_sequence[4]; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: uip_selectport() * * Description: * If the portnumber is zero; select an unused port for the connection. * If the portnumber 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 * ****************************************************************************/ static int uip_selectport(uint16 portno) { 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; } } while (uip_tcplistener(htons(g_last_tcp_port))); } else { /* A port number has been supplied. Verify that no other TCP/IP * connection is using this local port. */ if (uip_tcplistener(portno)) { /* It is in use... return EADDRINUSE */ return -EADDRINUSE; } } /* Return the selected or verified port number */ return portno; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: uip_tcpinit() * * Description: * Initialize the TCP/IP connection structures. Called only once and only * from the UIP layer at startup in normal user mode. * ****************************************************************************/ void uip_tcpinit(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 = UIP_CLOSED; dq_addlast(&g_tcp_connections[i].node, &g_free_tcp_connections); } g_last_tcp_port = 1024; } /**************************************************************************** * Name: uip_tcpalloc() * * 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" * ****************************************************************************/ struct uip_conn *uip_tcpalloc(void) { struct uip_conn *conn; irqstate_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 = irqsave(); /* Return the entry from the head of the free list */ conn = (struct uip_conn *)dq_remfirst(&g_free_tcp_connections); #if 0 /* Revisit */ /* Is the free list empty? */ if (!conn) { /* As a fallback, check for connection structures in the TIME_WAIT * state. If no CLOSED connections are found, then take the oldest */ struct uip_conn *tmp = g_active_tcp_connections.head; while (tmp) { /* Is this connectin in the UIP_TIME_WAIT state? */ if (tmp->tcpstateflags == UIP_TIME_WAIT) { /* 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 = tmp->node.flink; } /* If we found one, remove it from the active connection list */ dq_rem(&conn->node, &g_active_tcp_connections); } #endif irqrestore(flags); /* Mark the connection allocated */ if (conn) { conn->tcpstateflags = UIP_ALLOCATED; } return conn; } /**************************************************************************** * Name: uip_tcpfree() * * Description: * Free a connection structure that is no longer in use. This should be * done by the implementation of close() * ****************************************************************************/ void uip_tcpfree(struct uip_conn *conn) { #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 struct uip_readahead_s *readahead; #endif irqstate_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. */ flags = irqsave(); /* UIP_ALLOCATED means that that the connection is not in the active list * yet. */ if (conn->tcpstateflags != UIP_ALLOCATED) { /* Remove the connection from the active list */ dq_rem(&conn->node, &g_active_tcp_connections); } /* Release any read-ahead buffers attached to the connection */ #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 while ((readahead = (struct uip_readahead_s *)sq_remfirst(&conn->readahead)) != NULL) { uip_tcpreadaheadrelease(readahead); } #endif /* Remove any backlog attached to this connection */ #ifdef CONFIG_NET_TCPBACKLOG if (conn->backlog) { uip_backlogdestroy(conn); } /* If this connection is, itself, backlogged, then remove it from the * parent connection's backlog list. */ if (conn->blparent) { uip_backlogdelete(conn->blparent, conn); } #endif /* Mark the connection available and put it into the free list */ conn->tcpstateflags = UIP_CLOSED; dq_addlast(&conn->node, &g_free_tcp_connections); irqrestore(flags); } /**************************************************************************** * Name: uip_tcpactive() * * Description: * Find a connection structure that is the appropriate * connection to be used withi the provided TCP/IP header * * Assumptions: * This function is called from UIP logic at interrupt level * ****************************************************************************/ struct uip_conn *uip_tcpactive(struct uip_tcpip_hdr *buf) { struct uip_conn *conn = (struct uip_conn *)g_active_tcp_connections.head; in_addr_t srcipaddr = uip_ip4addr_conv(buf->srcipaddr); while (conn) { /* Find an open connection matching the tcp input */ if (conn->tcpstateflags != UIP_CLOSED && buf->destport == conn->lport && buf->srcport == conn->rport && uip_ipaddr_cmp(srcipaddr, conn->ripaddr)) { /* Matching connection found.. break out of the loop and return a * reference to it. */ break; } /* Look at the next active connection */ conn = (struct uip_conn *)conn->node.flink; } return conn; } /**************************************************************************** * Name: uip_nexttcpconn() * * Description: * Traverse the list of active TCP connections * * Assumptions: * This function is called from UIP logic at interrupt level (or with * interrupts disabled). * ****************************************************************************/ struct uip_conn *uip_nexttcpconn(struct uip_conn *conn) { if (!conn) { return (struct uip_conn *)g_active_tcp_connections.head; } else { return (struct uip_conn *)conn->node.flink; } } /**************************************************************************** * Name: uip_tcplistener() * * 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 idenfity the socket that will accept new connections on a local port. * ****************************************************************************/ struct uip_conn *uip_tcplistener(uint16 portno) { struct uip_conn *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]; if (conn->tcpstateflags != UIP_CLOSED && conn->lport == portno) { /* The portnumber is in use, return the connection */ return conn; } } return NULL; } /**************************************************************************** * Name: uip_tcpaccept() * * Description: * Called when uip_interupt 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 * ****************************************************************************/ struct uip_conn *uip_tcpaccept(struct uip_tcpip_hdr *buf) { struct uip_conn *conn = uip_tcpalloc(); if (conn) { /* Fill in the necessary fields for the new connection. */ conn->rto = UIP_RTO; conn->timer = UIP_RTO; conn->sa = 0; conn->sv = 4; conn->nrtx = 0; conn->lport = buf->destport; conn->rport = buf->srcport; uip_ipaddr_copy(conn->ripaddr, uip_ip4addr_conv(buf->srcipaddr)); conn->tcpstateflags = UIP_SYN_RCVD; memcpy(conn->snd_nxt, g_tcp_sequence, 4); conn->len = 1; /* rcv_nxt should be the seqno from the incoming packet + 1. */ memcpy(conn->rcv_nxt, buf->seqno, 4); /* Initialize the list of TCP read-ahead buffers */ #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 sq_init(&conn->readahead); #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: uip_tcpnextsequence() * * Description: * Increment the TCP/IP sequence number * * Assumptions: * This function is called from the interrupt level * ****************************************************************************/ void uip_tcpnextsequence(void) { /* This inplements a byte-by-byte big-endian increment */ if (++g_tcp_sequence[3] == 0) { if (++g_tcp_sequence[2] == 0) { if (++g_tcp_sequence[1] == 0) { ++g_tcp_sequence[0]; } } } } /**************************************************************************** * Name: uip_tcpbind() * * Description: * This function implements the UIP specific 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 uip_tcpbind(struct uip_conn *conn, const struct sockaddr_in6 *addr) #else int uip_tcpbind(struct uip_conn *conn, const struct sockaddr_in *addr) #endif { irqstate_t flags; int port; /* Verify or select a local port */ flags = irqsave(); port = uip_selectport(ntohs(addr->sin_port)); irqrestore(flags); if (port < 0) { return port; } /* Save the local address in the connection structure. Note that the requested * local IP address is saved but not used. At present, only a single network * interface is supported, the IP address is not of importance. */ conn->lport = addr->sin_port; #if 0 /* Not used */ #ifdef CONFIG_NET_IPv6 uip_ipaddr_copy(conn->lipaddr, addr->sin6_addr.in6_u.u6_addr16); #else uip_ipaddr_copy(conn->lipaddr, addr->sin_addr.s_addr); #endif #endif return OK; } /**************************************************************************** * Name: uip_tcpconnect() * * Description: * This function implements the UIP specific 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 specied 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 uip_tcpconnect(). * * Assumptions: * This function is called from normal user level code. * ****************************************************************************/ #ifdef CONFIG_NET_IPv6 int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in6 *addr) #else int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in *addr) #endif { irqstate_t flags; int port; /* The connection is expected to be in the UIP_ALLOCATED state.. i.e., * allocated via up_tcpalloc(), but not yet put into the active connections * list. */ if (!conn || conn->tcpstateflags != UIP_ALLOCATED) { return -EISCONN; } /* If the TCP port has not alread been bound to a local port, then select * one now. */ flags = irqsave(); port = uip_selectport(ntohs(conn->lport)); irqrestore(flags); if (port < 0) { return port; } /* Initialize and return the connection structure, bind it to the port number */ conn->tcpstateflags = UIP_SYN_SENT; memcpy(conn->snd_nxt, g_tcp_sequence, 4); conn->initialmss = conn->mss = UIP_TCP_MSS; conn->len = 1; /* TCP length of the SYN is one. */ conn->nrtx = 0; conn->timer = 1; /* Send the SYN next time around. */ conn->rto = UIP_RTO; conn->sa = 0; conn->sv = 16; /* Initial value of the RTT variance. */ conn->lport = htons((uint16)port); /* 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. */ uip_ipaddr_copy(conn->ripaddr, addr->sin_addr.s_addr); /* Initialize the list of TCP read-ahead buffers */ #if CONFIG_NET_NTCP_READAHEAD_BUFFERS > 0 sq_init(&conn->readahead); #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 = irqsave(); dq_addlast(&conn->node, &g_active_tcp_connections); irqrestore(flags); return OK; } #endif /* CONFIG_NET && CONFIG_NET_TCP */