diff options
Diffstat (limited to 'lib/lufa/Projects/Webserver/Lib/uip/uip.c')
| -rw-r--r-- | lib/lufa/Projects/Webserver/Lib/uip/uip.c | 1941 |
1 files changed, 1941 insertions, 0 deletions
diff --git a/lib/lufa/Projects/Webserver/Lib/uip/uip.c b/lib/lufa/Projects/Webserver/Lib/uip/uip.c new file mode 100644 index 0000000000..fead75775c --- /dev/null +++ b/lib/lufa/Projects/Webserver/Lib/uip/uip.c @@ -0,0 +1,1941 @@ +#define DEBUG_PRINTF(...) /*printf(__VA_ARGS__)*/ + +/** + * \addtogroup uip + * @{ + */ + +/** + * \file + * The uIP TCP/IP stack code. + * \author Adam Dunkels <adam@dunkels.com> + */ + +/* + * 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. + * + * This file is part of the uIP TCP/IP stack. + * + * $Id: uip.c,v 1.15 2008/10/15 08:08:32 adamdunkels Exp $ + * + */ + +/* + * uIP is a small implementation of the IP, UDP and TCP protocols (as + * well as some basic ICMP stuff). The implementation couples the IP, + * UDP, TCP and the application layers very tightly. To keep the size + * of the compiled code down, this code frequently uses the goto + * statement. While it would be possible to break the uip_process() + * function into many smaller functions, this would increase the code + * size because of the overhead of parameter passing and the fact that + * the optimizer would not be as efficient. + * + * The principle is that we have a small buffer, called the uip_buf, + * in which the device driver puts an incoming packet. The TCP/IP + * stack parses the headers in the packet, and calls the + * application. If the remote host has sent data to the application, + * this data is present in the uip_buf and the application read the + * data from there. It is up to the application to put this data into + * a byte stream if needed. The application will not be fed with data + * that is out of sequence. + * + * If the application whishes to send data to the peer, it should put + * its data into the uip_buf. The uip_appdata pointer points to the + * first available byte. The TCP/IP stack will calculate the + * checksums, and fill in the necessary header fields and finally send + * the packet back to the peer. +*/ + +#include "uip.h" +#include "uipopt.h" +#include "uip_arp.h" + +#if !UIP_CONF_IPV6 /* If UIP_CONF_IPV6 is defined, we compile the + uip6.c file instead of this one. Therefore + this #ifndef removes the entire compilation + output of the uip.c file */ + + +#if UIP_CONF_IPV6 +#include "net/uip-neighbor.h" +#endif /* UIP_CONF_IPV6 */ + +#include <string.h> + +/*---------------------------------------------------------------------------*/ +/* Variable definitions. */ + + +/* The IP address of this host. If it is defined to be fixed (by + setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set + here. Otherwise, the address */ +#if UIP_FIXEDADDR > 0 +const uip_ipaddr_t uip_hostaddr = + { UIP_IPADDR0, UIP_IPADDR1, UIP_IPADDR2, UIP_IPADDR3 }; +const uip_ipaddr_t uip_draddr = + { UIP_DRIPADDR0, UIP_DRIPADDR1, UIP_DRIPADDR2, UIP_DRIPADDR3 }; +const uip_ipaddr_t uip_netmask = + { UIP_NETMASK0, UIP_NETMASK1, UIP_NETMASK2, UIP_NETMASK3 }; +#else +uip_ipaddr_t uip_hostaddr, uip_draddr, uip_netmask; +#endif /* UIP_FIXEDADDR */ + +const uip_ipaddr_t uip_broadcast_addr = +#if UIP_CONF_IPV6 + { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } }; +#else /* UIP_CONF_IPV6 */ + { { 0xff, 0xff, 0xff, 0xff } }; +#endif /* UIP_CONF_IPV6 */ +const uip_ipaddr_t uip_all_zeroes_addr = { { 0x0, /* rest is 0 */ } }; + +#if UIP_FIXEDETHADDR +const struct uip_eth_addr uip_ethaddr = {{UIP_ETHADDR0, + UIP_ETHADDR1, + UIP_ETHADDR2, + UIP_ETHADDR3, + UIP_ETHADDR4, + UIP_ETHADDR5}}; +#else +struct uip_eth_addr uip_ethaddr = {{0,0,0,0,0,0}}; +#endif + +#ifndef UIP_CONF_EXTERNAL_BUFFER +u8_t uip_buf[UIP_BUFSIZE + 2]; /* The packet buffer that contains + incoming packets. */ +#endif /* UIP_CONF_EXTERNAL_BUFFER */ + +void *uip_appdata; /* The uip_appdata pointer points to + application data. */ +void *uip_sappdata; /* The uip_appdata pointer points to + the application data which is to + be sent. */ +#if UIP_URGDATA > 0 +void *uip_urgdata; /* The uip_urgdata pointer points to + urgent data (out-of-band data), if + present. */ +u16_t uip_urglen, uip_surglen; +#endif /* UIP_URGDATA > 0 */ + +u16_t uip_len, uip_slen; + /* The uip_len is either 8 or 16 bits, + depending on the maximum packet + size. */ + +u8_t uip_flags; /* The uip_flags variable is used for + communication between the TCP/IP stack + and the application program. */ +struct uip_conn *uip_conn; /* uip_conn always points to the current + connection. */ + +struct uip_conn uip_conns[UIP_CONNS]; + /* The uip_conns array holds all TCP + connections. */ +u16_t uip_listenports[UIP_LISTENPORTS]; + /* The uip_listenports list all currently + listening ports. */ +#if UIP_UDP +struct uip_udp_conn *uip_udp_conn; +struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS]; +#endif /* UIP_UDP */ + +static u16_t ipid; /* Ths ipid variable is an increasing + number that is used for the IP ID + field. */ + +void uip_setipid(u16_t id) { ipid = id; } + +static u8_t iss[4]; /* The iss variable is used for the TCP + initial sequence number. */ + +#if UIP_ACTIVE_OPEN +static u16_t lastport; /* Keeps track of the last port used for + a new connection. */ +#endif /* UIP_ACTIVE_OPEN */ + +/* Temporary variables. */ +u8_t uip_acc32[4]; +static u8_t c, opt; +static u16_t tmp16; + +/* Structures and definitions. */ +#define TCP_FIN 0x01 +#define TCP_SYN 0x02 +#define TCP_RST 0x04 +#define TCP_PSH 0x08 +#define TCP_ACK 0x10 +#define TCP_URG 0x20 +#define TCP_CTL 0x3f + +#define TCP_OPT_END 0 /* End of TCP options list */ +#define TCP_OPT_NOOP 1 /* "No-operation" TCP option */ +#define TCP_OPT_MSS 2 /* Maximum segment size TCP option */ + +#define TCP_OPT_MSS_LEN 4 /* Length of TCP MSS option. */ + +#define ICMP_ECHO_REPLY 0 +#define ICMP_ECHO 8 + +#define ICMP_DEST_UNREACHABLE 3 +#define ICMP_PORT_UNREACHABLE 3 + +#define ICMP6_ECHO_REPLY 129 +#define ICMP6_ECHO 128 +#define ICMP6_NEIGHBOR_SOLICITATION 135 +#define ICMP6_NEIGHBOR_ADVERTISEMENT 136 + +#define ICMP6_FLAG_S (1 << 6) + +#define ICMP6_OPTION_SOURCE_LINK_ADDRESS 1 +#define ICMP6_OPTION_TARGET_LINK_ADDRESS 2 + + +/* Macros. */ +#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN]) +#define FBUF ((struct uip_tcpip_hdr *)&uip_reassbuf[0]) +#define ICMPBUF ((struct uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN]) +#define UDPBUF ((struct uip_udpip_hdr *)&uip_buf[UIP_LLH_LEN]) + + +#if UIP_STATISTICS == 1 +struct uip_stats uip_stat; +#define UIP_STAT(s) s +#else +#define UIP_STAT(s) +#endif /* UIP_STATISTICS == 1 */ + +#if UIP_LOGGING == 1 +#include <stdio.h> +void uip_log(char *msg); +#define UIP_LOG(m) uip_log(m) +#else +#define UIP_LOG(m) +#endif /* UIP_LOGGING == 1 */ + +#if ! UIP_ARCH_ADD32 +void +uip_add32(u8_t *op32, u16_t op16) +{ + uip_acc32[3] = op32[3] + (op16 & 0xff); + uip_acc32[2] = op32[2] + (op16 >> 8); + uip_acc32[1] = op32[1]; + uip_acc32[0] = op32[0]; + + if(uip_acc32[2] < (op16 >> 8)) { + ++uip_acc32[1]; + if(uip_acc32[1] == 0) { + ++uip_acc32[0]; + } + } + + + if(uip_acc32[3] < (op16 & 0xff)) { + ++uip_acc32[2]; + if(uip_acc32[2] == 0) { + ++uip_acc32[1]; + if(uip_acc32[1] == 0) { + ++uip_acc32[0]; + } + } + } +} + +#endif /* UIP_ARCH_ADD32 */ + +#if ! UIP_ARCH_CHKSUM +/*---------------------------------------------------------------------------*/ +static u16_t +chksum(u16_t sum, const u8_t *data, u16_t len) +{ + u16_t t; + const u8_t *dataptr; + const u8_t *last_byte; + + dataptr = data; + last_byte = data + len - 1; + + while(dataptr < last_byte) { /* At least two more bytes */ + t = (dataptr[0] << 8) + dataptr[1]; + sum += t; + if(sum < t) { + sum++; /* carry */ + } + dataptr += 2; + } + + if(dataptr == last_byte) { + t = (dataptr[0] << 8) + 0; + sum += t; + if(sum < t) { + sum++; /* carry */ + } + } + + /* Return sum in host byte order. */ + return sum; +} +/*---------------------------------------------------------------------------*/ +u16_t +uip_chksum(u16_t *data, u16_t len) +{ + return htons(chksum(0, (u8_t *)data, len)); +} +/*---------------------------------------------------------------------------*/ +#ifndef UIP_ARCH_IPCHKSUM +u16_t +uip_ipchksum(void) +{ + u16_t sum; + + sum = chksum(0, &uip_buf[UIP_LLH_LEN], UIP_IPH_LEN); + DEBUG_PRINTF("uip_ipchksum: sum 0x%04x\n", sum); + return (sum == 0) ? 0xffff : htons(sum); +} +#endif +/*---------------------------------------------------------------------------*/ +static u16_t +upper_layer_chksum(u8_t proto) +{ + u16_t upper_layer_len; + u16_t sum; + +#if UIP_CONF_IPV6 + upper_layer_len = (((u16_t)(BUF->len[0]) << 8) + BUF->len[1]); +#else /* UIP_CONF_IPV6 */ + upper_layer_len = (((u16_t)(BUF->len[0]) << 8) + BUF->len[1]) - UIP_IPH_LEN; +#endif /* UIP_CONF_IPV6 */ + + /* First sum pseudo-header. */ + + /* IP protocol and length fields. This addition cannot carry. */ + sum = upper_layer_len + proto; + /* Sum IP source and destination addresses. */ + sum = chksum(sum, (u8_t *)&BUF->srcipaddr, 2 * sizeof(uip_ipaddr_t)); + + /* Sum TCP header and data. */ + sum = chksum(sum, &uip_buf[UIP_IPH_LEN + UIP_LLH_LEN], + upper_layer_len); + + return (sum == 0) ? 0xffff : htons(sum); +} +/*---------------------------------------------------------------------------*/ +#if UIP_CONF_IPV6 +u16_t +uip_icmp6chksum(void) +{ + return upper_layer_chksum(UIP_PROTO_ICMP6); + +} +#endif /* UIP_CONF_IPV6 */ +/*---------------------------------------------------------------------------*/ +u16_t +uip_tcpchksum(void) +{ + return upper_layer_chksum(UIP_PROTO_TCP); +} +/*---------------------------------------------------------------------------*/ +#if UIP_UDP_CHECKSUMS +u16_t +uip_udpchksum(void) +{ + return upper_layer_chksum(UIP_PROTO_UDP); +} +#endif /* UIP_UDP_CHECKSUMS */ +#endif /* UIP_ARCH_CHKSUM */ +/*---------------------------------------------------------------------------*/ +void +uip_init(void) +{ + for(c = 0; c < UIP_LISTENPORTS; ++c) { + uip_listenports[c] = 0; + } + for(c = 0; c < UIP_CONNS; ++c) { + uip_conns[c].tcpstateflags = UIP_CLOSED; + } +#if UIP_ACTIVE_OPEN + lastport = 1024; +#endif /* UIP_ACTIVE_OPEN */ + +#if UIP_UDP + for(c = 0; c < UIP_UDP_CONNS; ++c) { + uip_udp_conns[c].lport = 0; + } +#endif /* UIP_UDP */ + + + /* IPv4 initialization. */ +#if UIP_FIXEDADDR == 0 + /* uip_hostaddr[0] = uip_hostaddr[1] = 0;*/ +#endif /* UIP_FIXEDADDR */ + +} +/*---------------------------------------------------------------------------*/ +#if UIP_ACTIVE_OPEN +struct uip_conn * +uip_connect(uip_ipaddr_t *ripaddr, u16_t rport) +{ + register struct uip_conn *conn, *cconn; + + /* Find an unused local port. */ + again: + ++lastport; + + if(lastport >= 32000) { + lastport = 4096; + } + + /* Check if this port is already in use, and if so try to find + another one. */ + for(c = 0; c < UIP_CONNS; ++c) { + conn = &uip_conns[c]; + if(conn->tcpstateflags != UIP_CLOSED && + conn->lport == htons(lastport)) { + goto again; + } + } + + conn = 0; + for(c = 0; c < UIP_CONNS; ++c) { + cconn = &uip_conns[c]; + if(cconn->tcpstateflags == UIP_CLOSED) { + conn = cconn; + break; + } + if(cconn->tcpstateflags == UIP_TIME_WAIT) { + if(conn == 0 || + cconn->timer > conn->timer) { + conn = cconn; + } + } + } + + if(conn == 0) { + return 0; + } + + conn->tcpstateflags = UIP_SYN_SENT; + + conn->snd_nxt[0] = iss[0]; + conn->snd_nxt[1] = iss[1]; + conn->snd_nxt[2] = iss[2]; + conn->snd_nxt[3] = iss[3]; + + 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(lastport); + conn->rport = rport; + uip_ipaddr_copy(&conn->ripaddr, ripaddr); + + return conn; +} +#endif /* UIP_ACTIVE_OPEN */ +/*---------------------------------------------------------------------------*/ +#if UIP_UDP +struct uip_udp_conn * +uip_udp_new(const uip_ipaddr_t *ripaddr, u16_t rport) +{ + register struct uip_udp_conn *conn; + + /* Find an unused local port. */ + again: + ++lastport; + + if(lastport >= 32000) { + lastport = 4096; + } + + for(c = 0; c < UIP_UDP_CONNS; ++c) { + if(uip_udp_conns[c].lport == htons(lastport)) { + goto again; + } + } + + + conn = 0; + for(c = 0; c < UIP_UDP_CONNS; ++c) { + if(uip_udp_conns[c].lport == 0) { + conn = &uip_udp_conns[c]; + break; + } + } + + if(conn == 0) { + return 0; + } + + conn->lport = HTONS(lastport); + conn->rport = rport; + if(ripaddr == NULL) { + memset(&conn->ripaddr, 0, sizeof(uip_ipaddr_t)); + } else { + uip_ipaddr_copy(&conn->ripaddr, ripaddr); + } + conn->ttl = UIP_TTL; + + return conn; +} +#endif /* UIP_UDP */ +/*---------------------------------------------------------------------------*/ +void +uip_unlisten(u16_t port) +{ + for(c = 0; c < UIP_LISTENPORTS; ++c) { + if(uip_listenports[c] == port) { + uip_listenports[c] = 0; + return; + } + } +} +/*---------------------------------------------------------------------------*/ +void +uip_listen(u16_t port) +{ + for(c = 0; c < UIP_LISTENPORTS; ++c) { + if(uip_listenports[c] == 0) { + uip_listenports[c] = port; + return; + } + } +} +/*---------------------------------------------------------------------------*/ +/* XXX: IP fragment reassembly: not well-tested. */ + +#if UIP_REASSEMBLY && !UIP_CONF_IPV6 +#define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN) +static u8_t uip_reassbuf[UIP_REASS_BUFSIZE]; +static u8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)]; +static const u8_t bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f, + 0x0f, 0x07, 0x03, 0x01}; +static u16_t uip_reasslen; +static u8_t uip_reassflags; +#define UIP_REASS_FLAG_LASTFRAG 0x01 +static u8_t uip_reasstmr; + +#define IP_MF 0x20 + +static u8_t +uip_reass(void) +{ + u16_t offset, len; + u16_t i; + + /* If ip_reasstmr is zero, no packet is present in the buffer, so we + write the IP header of the fragment into the reassembly + buffer. The timer is updated with the maximum age. */ + if(uip_reasstmr == 0) { + memcpy(uip_reassbuf, &BUF->vhl, UIP_IPH_LEN); + uip_reasstmr = UIP_REASS_MAXAGE; + uip_reassflags = 0; + /* Clear the bitmap. */ + memset(uip_reassbitmap, 0, sizeof(uip_reassbitmap)); + } + + /* Check if the incoming fragment matches the one currently present + in the reasembly buffer. If so, we proceed with copying the + fragment into the buffer. */ + if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] && + BUF->srcipaddr[1] == FBUF->srcipaddr[1] && + BUF->destipaddr[0] == FBUF->destipaddr[0] && + BUF->destipaddr[1] == FBUF->destipaddr[1] && + BUF->ipid[0] == FBUF->ipid[0] && + BUF->ipid[1] == FBUF->ipid[1]) { + + len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4; + offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8; + + /* If the offset or the offset + fragment length overflows the + reassembly buffer, we discard the entire packet. */ + if(offset > UIP_REASS_BUFSIZE || + offset + len > UIP_REASS_BUFSIZE) { + uip_reasstmr = 0; + goto nullreturn; + } + + /* Copy the fragment into the reassembly buffer, at the right + offset. */ + memcpy(&uip_reassbuf[UIP_IPH_LEN + offset], + (char *)BUF + (int)((BUF->vhl & 0x0f) * 4), + len); + + /* Update the bitmap. */ + if(offset / (8 * 8) == (offset + len) / (8 * 8)) { + /* If the two endpoints are in the same byte, we only update + that byte. */ + + uip_reassbitmap[offset / (8 * 8)] |= + bitmap_bits[(offset / 8 ) & 7] & + ~bitmap_bits[((offset + len) / 8 ) & 7]; + } else { + /* If the two endpoints are in different bytes, we update the + bytes in the endpoints and fill the stuff in-between with + 0xff. */ + uip_reassbitmap[offset / (8 * 8)] |= + bitmap_bits[(offset / 8 ) & 7]; + for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) { + uip_reassbitmap[i] = 0xff; + } + uip_reassbitmap[(offset + len) / (8 * 8)] |= + ~bitmap_bits[((offset + len) / 8 ) & 7]; + } + + /* If this fragment has the More Fragments flag set to zero, we + know that this is the last fragment, so we can calculate the + size of the entire packet. We also set the + IP_REASS_FLAG_LASTFRAG flag to indicate that we have received + the final fragment. */ + + if((BUF->ipoffset[0] & IP_MF) == 0) { + uip_reassflags |= UIP_REASS_FLAG_LASTFRAG; + uip_reasslen = offset + len; + } + + /* Finally, we check if we have a full packet in the buffer. We do + this by checking if we have the last fragment and if all bits + in the bitmap are set. */ + if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) { + /* Check all bytes up to and including all but the last byte in + the bitmap. */ + for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) { + if(uip_reassbitmap[i] != 0xff) { + goto nullreturn; + } + } + /* Check the last byte in the bitmap. It should contain just the + right amount of bits. */ + if(uip_reassbitmap[uip_reasslen / (8 * 8)] != + (u8_t)~bitmap_bits[uip_reasslen / 8 & 7]) { + goto nullreturn; + } + + /* If we have come this far, we have a full packet in the + buffer, so we allocate a pbuf and copy the packet into it. We + also reset the timer. */ + uip_reasstmr = 0; + memcpy(BUF, FBUF, uip_reasslen); + + /* Pretend to be a "normal" (i.e., not fragmented) IP packet + from now on. */ + BUF->ipoffset[0] = BUF->ipoffset[1] = 0; + BUF->len[0] = uip_reasslen >> 8; + BUF->len[1] = uip_reasslen & 0xff; + BUF->ipchksum = 0; + BUF->ipchksum = ~(uip_ipchksum()); + + return uip_reasslen; + } + } + + nullreturn: + return 0; +} +#endif /* UIP_REASSEMBLY */ +/*---------------------------------------------------------------------------*/ +static void +uip_add_rcv_nxt(u16_t n) +{ + uip_add32(uip_conn->rcv_nxt, n); + uip_conn->rcv_nxt[0] = uip_acc32[0]; + uip_conn->rcv_nxt[1] = uip_acc32[1]; + uip_conn->rcv_nxt[2] = uip_acc32[2]; + uip_conn->rcv_nxt[3] = uip_acc32[3]; +} +/*---------------------------------------------------------------------------*/ +void +uip_process(u8_t flag) +{ + register struct uip_conn *uip_connr = uip_conn; + +#if UIP_UDP + if(flag == UIP_UDP_SEND_CONN) { + goto udp_send; + } +#endif /* UIP_UDP */ + + uip_sappdata = uip_appdata = &uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN]; + + /* Check if we were invoked because of a poll request for a + particular connection. */ + if(flag == UIP_POLL_REQUEST) { + if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED && + !uip_outstanding(uip_connr)) { + uip_len = uip_slen = 0; + uip_flags = UIP_POLL; + UIP_APPCALL(); + goto appsend; + } + goto drop; + + /* Check if we were invoked because of the periodic timer firing. */ + } else if(flag == UIP_TIMER) { +#if UIP_REASSEMBLY + if(uip_reasstmr != 0) { + --uip_reasstmr; + } +#endif /* UIP_REASSEMBLY */ + /* Increase the initial sequence number. */ + if(++iss[3] == 0) { + if(++iss[2] == 0) { + if(++iss[1] == 0) { + ++iss[0]; + } + } + } + + /* Reset the length variables. */ + uip_len = 0; + uip_slen = 0; + + /* Check if the connection is in a state in which we simply wait + for the connection to time out. If so, we increase the + connection's timer and remove the connection if it times + out. */ + if(uip_connr->tcpstateflags == UIP_TIME_WAIT || + uip_connr->tcpstateflags == UIP_FIN_WAIT_2) { + ++(uip_connr->timer); + if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) { + uip_connr->tcpstateflags = UIP_CLOSED; + } + } else if(uip_connr->tcpstateflags != UIP_CLOSED) { + /* If the connection has outstanding data, we increase the + connection's timer and see if it has reached the RTO value + in which case we retransmit. */ + if(uip_outstanding(uip_connr)) { + if(uip_connr->timer-- == 0) { + if(uip_connr->nrtx == UIP_MAXRTX || + ((uip_connr->tcpstateflags == UIP_SYN_SENT || + uip_connr->tcpstateflags == UIP_SYN_RCVD) && + uip_connr->nrtx == UIP_MAXSYNRTX)) { + uip_connr->tcpstateflags = UIP_CLOSED; + + /* We call UIP_APPCALL() with uip_flags set to + UIP_TIMEDOUT to inform the application that the + connection has timed out. */ + uip_flags = UIP_TIMEDOUT; + UIP_APPCALL(); + + /* We also send a reset packet to the remote host. */ + BUF->flags = TCP_RST | TCP_ACK; + goto tcp_send_nodata; + } + + /* Exponential back-off. */ + uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4? + 4: + uip_connr->nrtx); + ++(uip_connr->nrtx); + + /* Ok, so we need to retransmit. We do this differently + depending on which state we are in. In ESTABLISHED, we + call upon the application so that it may prepare the + data for the retransmit. In SYN_RCVD, we resend the + SYNACK that we sent earlier and in LAST_ACK we have to + retransmit our FINACK. */ + UIP_STAT(++uip_stat.tcp.rexmit); + switch(uip_connr->tcpstateflags & UIP_TS_MASK) { + case UIP_SYN_RCVD: + /* In the SYN_RCVD state, we should retransmit our + SYNACK. */ + goto tcp_send_synack; + +#if UIP_ACTIVE_OPEN + case UIP_SYN_SENT: + /* In the SYN_SENT state, we retransmit out SYN. */ + BUF->flags = 0; + goto tcp_send_syn; +#endif /* UIP_ACTIVE_OPEN */ + + case UIP_ESTABLISHED: + /* In the ESTABLISHED state, we call upon the application + to do the actual retransmit after which we jump into + the code for sending out the packet (the apprexmit + label). */ + uip_flags = UIP_REXMIT; + UIP_APPCALL(); + goto apprexmit; + + case UIP_FIN_WAIT_1: + case UIP_CLOSING: + case UIP_LAST_ACK: + /* In all these states we should retransmit a FINACK. */ + goto tcp_send_finack; + + } + } + } else if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED) { + /* If there was no need for a retransmission, we poll the + application for new data. */ + uip_len = uip_slen = 0; + uip_flags = UIP_POLL; + UIP_APPCALL(); + goto appsend; + } + } + goto drop; + } +#if UIP_UDP + if(flag == UIP_UDP_TIMER) { + if(uip_udp_conn->lport != 0) { + uip_conn = NULL; + uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN]; + uip_len = uip_slen = 0; + uip_flags = UIP_POLL; + UIP_UDP_APPCALL(); + goto udp_send; + } else { + goto drop; + } + } +#endif + + /* This is where the input processing starts. */ + UIP_STAT(++uip_stat.ip.recv); + + /* Start of IP input header processing code. */ + +#if UIP_CONF_IPV6 + /* Check validity of the IP header. */ + if((BUF->vtc & 0xf0) != 0x60) { /* IP version and header length. */ + UIP_STAT(++uip_stat.ip.drop); + UIP_STAT(++uip_stat.ip.vhlerr); + UIP_LOG("ipv6: invalid version."); + goto drop; + } +#else /* UIP_CONF_IPV6 */ + /* Check validity of the IP header. */ + if(BUF->vhl != 0x45) { /* IP version and header length. */ + UIP_STAT(++uip_stat.ip.drop); + UIP_STAT(++uip_stat.ip.vhlerr); + UIP_LOG("ip: invalid version or header length."); + goto drop; + } +#endif /* UIP_CONF_IPV6 */ + + /* Check the size of the packet. If the size reported to us in + uip_len is smaller the size reported in the IP header, we assume + that the packet has been corrupted in transit. If the size of + uip_len is larger than the size reported in the IP packet header, + the packet has been padded and we set uip_len to the correct + value.. */ + + if((BUF->len[0] << 8) + BUF->len[1] <= uip_len) { + uip_len = (BUF->len[0] << 8) + BUF->len[1]; +#if UIP_CONF_IPV6 + uip_len += 40; /* The length reported in the IPv6 header is the + length of the payload that follows the + header. However, uIP uses the uip_len variable + for holding the size of the entire packet, + including the IP header. For IPv4 this is not a + problem as the length field in the IPv4 header + contains the length of the entire packet. But + for IPv6 we need to add the size of the IPv6 + header (40 bytes). */ +#endif /* UIP_CONF_IPV6 */ + } else { + UIP_LOG("ip: packet shorter than reported in IP header."); + goto drop; + } + +#if !UIP_CONF_IPV6 + /* Check the fragment flag. */ + if((BUF->ipoffset[0] & 0x3f) != 0 || + BUF->ipoffset[1] != 0) { +#if UIP_REASSEMBLY + uip_len = uip_reass(); + if(uip_len == 0) { + goto drop; + } +#else /* UIP_REASSEMBLY */ + UIP_STAT(++uip_stat.ip.drop); + UIP_STAT(++uip_stat.ip.fragerr); + UIP_LOG("ip: fragment dropped."); + goto drop; +#endif /* UIP_REASSEMBLY */ + } +#endif /* UIP_CONF_IPV6 */ + + if(uip_ipaddr_cmp(&uip_hostaddr, &uip_all_zeroes_addr)) { + /* If we are configured to use ping IP address configuration and + hasn't been assigned an IP address yet, we accept all ICMP + packets. */ +#if UIP_PINGADDRCONF && !UIP_CONF_IPV6 + if(BUF->proto == UIP_PROTO_ICMP) { + UIP_LOG("ip: possible ping config packet received."); + goto icmp_input; + } else { + UIP_LOG("ip: packet dropped since no address assigned."); + goto drop; + } +#endif /* UIP_PINGADDRCONF */ + + } else { + /* If IP broadcast support is configured, we check for a broadcast + UDP packet, which may be destined to us. */ +#if UIP_BROADCAST + DEBUG_PRINTF("UDP IP checksum 0x%04x\n", uip_ipchksum()); + if(BUF->proto == UIP_PROTO_UDP && + uip_ipaddr_cmp(&BUF->destipaddr, &uip_broadcast_addr)) + { + if (uip_ipaddr_cmp(&BUF->srcipaddr, &uip_all_zeroes_addr)) + uip_ipaddr_copy(&BUF->srcipaddr, &uip_broadcast_addr); + + goto udp_input; + } +#endif /* UIP_BROADCAST */ + + /* Check if the packet is destined for our IP address. */ +#if !UIP_CONF_IPV6 + if(!uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr)) { + UIP_STAT(++uip_stat.ip.drop); + goto drop; + } +#else /* UIP_CONF_IPV6 */ + /* For IPv6, packet reception is a little trickier as we need to + make sure that we listen to certain multicast addresses (all + hosts multicast address, and the solicited-node multicast + address) as well. However, we will cheat here and accept all + multicast packets that are sent to the ff02::/16 addresses. */ + if(!uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr) && + BUF->destipaddr.u16[0] != HTONS(0xff02)) { + UIP_STAT(++uip_stat.ip.drop); + goto drop; + } +#endif /* UIP_CONF_IPV6 */ + } + +#if !UIP_CONF_IPV6 + if(uip_ipchksum() != 0xffff) { /* Compute and check the IP header + checksum. */ + UIP_STAT(++uip_stat.ip.drop); + UIP_STAT(++uip_stat.ip.chkerr); + UIP_LOG("ip: bad checksum."); + goto drop; + } +#endif /* UIP_CONF_IPV6 */ + + if(BUF->proto == UIP_PROTO_TCP) { /* Check for TCP packet. If so, + proceed with TCP input + processing. */ + goto tcp_input; + } + +#if UIP_UDP + if(BUF->proto == UIP_PROTO_UDP) { + goto udp_input; + } +#endif /* UIP_UDP */ + +#if !UIP_CONF_IPV6 + /* ICMPv4 processing code follows. */ + if(BUF->proto != UIP_PROTO_ICMP) { /* We only allow ICMP packets from + here. */ + UIP_STAT(++uip_stat.ip.drop); + UIP_STAT(++uip_stat.ip.protoerr); + UIP_LOG("ip: neither tcp nor icmp."); + goto drop; + } + +#if UIP_PINGADDRCONF + icmp_input: +#endif /* UIP_PINGADDRCONF */ + UIP_STAT(++uip_stat.icmp.recv); + + /* ICMP echo (i.e., ping) processing. This is simple, we only change + the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP + checksum before we return the packet. */ + if(ICMPBUF->type != ICMP_ECHO) { + UIP_STAT(++uip_stat.icmp.drop); + UIP_STAT(++uip_stat.icmp.typeerr); + UIP_LOG("icmp: not icmp echo."); + goto drop; + } + + /* If we are configured to use ping IP address assignment, we use + the destination IP address of this ping packet and assign it to + yourself. */ +#if UIP_PINGADDRCONF + if(uip_ipaddr_cmp(&uip_hostaddr, &uip_all_zeroes_addr)) { + uip_hostaddr = BUF->destipaddr; + } +#endif /* UIP_PINGADDRCONF */ + + ICMPBUF->type = ICMP_ECHO_REPLY; + + if(ICMPBUF->icmpchksum >= HTONS(0xffff - (ICMP_ECHO << 8))) { + ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8) + 1; + } else { + ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8); + } + + /* Swap IP addresses. */ + uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr); + uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr); + + UIP_STAT(++uip_stat.icmp.sent); + BUF->ttl = UIP_TTL; + goto ip_send_nolen; + + /* End of IPv4 input header processing code. */ +#else /* !UIP_CONF_IPV6 */ + + /* This is IPv6 ICMPv6 processing code. */ + DEBUG_PRINTF("icmp6_input: length %d\n", uip_len); + + if(BUF->proto != UIP_PROTO_ICMP6) { /* We only allow ICMPv6 packets from + here. */ + UIP_STAT(++uip_stat.ip.drop); + UIP_STAT(++uip_stat.ip.protoerr); + UIP_LOG("ip: neither tcp nor icmp6."); + goto drop; + } + + UIP_STAT(++uip_stat.icmp.recv); + + /* If we get a neighbor solicitation for our address we should send + a neighbor advertisement message back. */ + if(ICMPBUF->type == ICMP6_NEIGHBOR_SOLICITATION) { + if(uip_ipaddr_cmp(&ICMPBUF->icmp6data, &uip_hostaddr)) { + + if(ICMPBUF->options[0] == ICMP6_OPTION_SOURCE_LINK_ADDRESS) { + /* Save the sender's address in our neighbor list. */ + uip_neighbor_add(&ICMPBUF->srcipaddr, &(ICMPBUF->options[2])); + } + + /* We should now send a neighbor advertisement back to where the + neighbor solicitation came from. */ + ICMPBUF->type = ICMP6_NEIGHBOR_ADVERTISEMENT; + ICMPBUF->flags = ICMP6_FLAG_S; /* Solicited flag. */ + + ICMPBUF->reserved1 = ICMPBUF->reserved2 = ICMPBUF->reserved3 = 0; + + uip_ipaddr_copy(&ICMPBUF->destipaddr, &ICMPBUF->srcipaddr); + uip_ipaddr_copy(&ICMPBUF->srcipaddr, &uip_hostaddr); + ICMPBUF->options[0] = ICMP6_OPTION_TARGET_LINK_ADDRESS; + ICMPBUF->options[1] = 1; /* Options length, 1 = 8 bytes. */ + memcpy(&(ICMPBUF->options[2]), &uip_ethaddr, sizeof(uip_ethaddr)); + ICMPBUF->icmpchksum = 0; + ICMPBUF->icmpchksum = ~uip_icmp6chksum(); + + goto send; + + } + goto drop; + } else if(ICMPBUF->type == ICMP6_ECHO) { + /* ICMP echo (i.e., ping) processing. This is simple, we only + change the ICMP type from ECHO to ECHO_REPLY and update the + ICMP checksum before we return the packet. */ + + ICMPBUF->type = ICMP6_ECHO_REPLY; + + uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr); + uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr); + ICMPBUF->icmpchksum = 0; + ICMPBUF->icmpchksum = ~uip_icmp6chksum(); + + UIP_STAT(++uip_stat.icmp.sent); + goto send; + } else { + DEBUG_PRINTF("Unknown icmp6 message type %d\n", ICMPBUF->type); + UIP_STAT(++uip_stat.icmp.drop); + UIP_STAT(++uip_stat.icmp.typeerr); + UIP_LOG("icmp: unknown ICMP message."); + goto drop; + } + + /* End of IPv6 ICMP processing. */ + +#endif /* !UIP_CONF_IPV6 */ + +#if UIP_UDP + /* UDP input processing. */ + udp_input: + /* UDP processing is really just a hack. We don't do anything to the + UDP/IP headers, but let the UDP application do all the hard + work. If the application sets uip_slen, it has a packet to + send. */ +#if UIP_UDP_CHECKSUMS + uip_len = uip_len - UIP_IPUDPH_LEN; + uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN]; + if(UDPBUF->udpchksum != 0 && uip_udpchksum() != 0xffff) { + UIP_STAT(++uip_stat.udp.drop); + UIP_STAT(++uip_stat.udp.chkerr); + UIP_LOG("udp: bad checksum."); + goto drop; + } +#else /* UIP_UDP_CHECKSUMS */ + uip_len = uip_len - UIP_IPUDPH_LEN; +#endif /* UIP_UDP_CHECKSUMS */ + + /* Demultiplex this UDP packet between the UDP "connections". */ + for(uip_udp_conn = &uip_udp_conns[0]; + uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS]; + ++uip_udp_conn) { + /* If the local UDP port is non-zero, the connection is considered + to be used. If so, the local port number is checked against the + destination port number in the received packet. If the two port + numbers match, the remote port number is checked if the + connection is bound to a remote port. Finally, if the + connection is bound to a remote IP address, the source IP + address of the packet is checked. */ + if(uip_udp_conn->lport != 0 && + UDPBUF->destport == uip_udp_conn->lport && + (uip_udp_conn->rport == 0 || + UDPBUF->srcport == uip_udp_conn->rport) && + (uip_ipaddr_cmp(&uip_udp_conn->ripaddr, &uip_all_zeroes_addr) || + uip_ipaddr_cmp(&uip_udp_conn->ripaddr, &uip_broadcast_addr) || + uip_ipaddr_cmp(&BUF->srcipaddr, &uip_udp_conn->ripaddr))) { + goto udp_found; + } + } + UIP_LOG("udp: no matching connection found"); +#if UIP_CONF_ICMP_DEST_UNREACH && !UIP_CONF_IPV6 + /* Copy fields from packet header into payload of this ICMP packet. */ + memcpy(&(ICMPBUF->payload[0]), ICMPBUF, UIP_IPH_LEN + 8); + + /* Set the ICMP type and code. */ + ICMPBUF->type = ICMP_DEST_UNREACHABLE; + ICMPBUF->icode = ICMP_PORT_UNREACHABLE; + + /* Calculate the ICMP checksum. */ + ICMPBUF->icmpchksum = 0; + ICMPBUF->icmpchksum = ~uip_chksum((u16_t *)&(ICMPBUF->type), 36); + + /* Set the IP destination address to be the source address of the + original packet. */ + uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr); + + /* Set our IP address as the source address. */ + uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr); + + /* The size of the ICMP destination unreachable packet is 36 + the + size of the IP header (20) = 56. */ + uip_len = 36 + UIP_IPH_LEN; + ICMPBUF->len[0] = 0; + ICMPBUF->len[1] = (u8_t)uip_len; + ICMPBUF->ttl = UIP_TTL; + ICMPBUF->proto = UIP_PROTO_ICMP; + + goto ip_send_nolen; +#else /* UIP_CONF_ICMP_DEST_UNREACH */ + goto drop; +#endif /* UIP_CONF_ICMP_DEST_UNREACH */ + + udp_found: + uip_conn = NULL; + uip_flags = UIP_NEWDATA; + uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN]; + uip_slen = 0; + UIP_UDP_APPCALL(); + + udp_send: + if(uip_slen == 0) { + goto drop; + } + uip_len = uip_slen + UIP_IPUDPH_LEN; + +#if UIP_CONF_IPV6 + /* For IPv6, the IP length field does not include the IPv6 IP header + length. */ + BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8); + BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff); +#else /* UIP_CONF_IPV6 */ + BUF->len[0] = (uip_len >> 8); + BUF->len[1] = (uip_len & 0xff); +#endif /* UIP_CONF_IPV6 */ + + BUF->ttl = uip_udp_conn->ttl; + BUF->proto = UIP_PROTO_UDP; + + UDPBUF->udplen = HTONS(uip_slen + UIP_UDPH_LEN); + UDPBUF->udpchksum = 0; + + BUF->srcport = uip_udp_conn->lport; + BUF->destport = uip_udp_conn->rport; + + uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr); + uip_ipaddr_copy(&BUF->destipaddr, &uip_udp_conn->ripaddr); + + uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPTCPH_LEN]; + +#if UIP_UDP_CHECKSUMS + /* Calculate UDP checksum. */ + UDPBUF->udpchksum = ~(uip_udpchksum()); + if(UDPBUF->udpchksum == 0) { + UDPBUF->udpchksum = 0xffff; + } +#endif /* UIP_UDP_CHECKSUMS */ + + goto ip_send_nolen; +#endif /* UIP_UDP */ + + /* TCP input processing. */ + tcp_input: + UIP_STAT(++uip_stat.tcp.recv); + + /* Start of TCP input header processing code. */ + + if(uip_tcpchksum() != 0xffff) { /* Compute and check the TCP + checksum. */ + UIP_STAT(++uip_stat.tcp.drop); + UIP_STAT(++uip_stat.tcp.chkerr); + UIP_LOG("tcp: bad checksum."); + goto drop; + } + + /* Demultiplex this segment. */ + /* First check any active connections. */ + for(uip_connr = &uip_conns[0]; uip_connr <= &uip_conns[UIP_CONNS - 1]; + ++uip_connr) { + if(uip_connr->tcpstateflags != UIP_CLOSED && + BUF->destport == uip_connr->lport && + BUF->srcport == uip_connr->rport && + uip_ipaddr_cmp(&BUF->srcipaddr, &uip_connr->ripaddr)) { + goto found; + } + } + + /* If we didn't find and active connection that expected the packet, + either this packet is an old duplicate, or this is a SYN packet + destined for a connection in LISTEN. If the SYN flag isn't set, + it is an old packet and we send a RST. */ + if((BUF->flags & TCP_CTL) != TCP_SYN) { + goto reset; + } + + tmp16 = BUF->destport; + /* Next, check listening connections. */ + for(c = 0; c < UIP_LISTENPORTS; ++c) { + if(tmp16 == uip_listenports[c]) { + goto found_listen; + } + } + + /* No matching connection found, so we send a RST packet. */ + UIP_STAT(++uip_stat.tcp.synrst); + + reset: + /* We do not send resets in response to resets. */ + if(BUF->flags & TCP_RST) { + goto drop; + } + + UIP_STAT(++uip_stat.tcp.rst); + + BUF->flags = TCP_RST | TCP_ACK; + uip_len = UIP_IPTCPH_LEN; + BUF->tcpoffset = 5 << 4; + + /* Flip the seqno and ackno fields in the TCP header. */ + c = BUF->seqno[3]; + BUF->seqno[3] = BUF->ackno[3]; + BUF->ackno[3] = c; + + c = BUF->seqno[2]; + BUF->seqno[2] = BUF->ackno[2]; + BUF->ackno[2] = c; + + c = BUF->seqno[1]; + BUF->seqno[1] = BUF->ackno[1]; + BUF->ackno[1] = c; + + c = BUF->seqno[0]; + BUF->seqno[0] = BUF->ackno[0]; + BUF->ackno[0] = c; + + /* We also have to increase the sequence number we are + acknowledging. If the least significant byte overflowed, we need + to propagate the carry to the other bytes as well. */ + if(++BUF->ackno[3] == 0) { + if(++BUF->ackno[2] == 0) { + if(++BUF->ackno[1] == 0) { + ++BUF->ackno[0]; + } + } + } + + /* Swap port numbers. */ + tmp16 = BUF->srcport; + BUF->srcport = BUF->destport; + BUF->destport = tmp16; + + /* Swap IP addresses. */ + uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr); + uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr); + + /* And send out the RST packet! */ + goto tcp_send_noconn; + + /* This label will be jumped to if we matched the incoming packet + with a connection in LISTEN. In that case, we should create a new + connection and send a SYNACK in return. */ + found_listen: + /* First we check if there are any connections available. Unused + connections are kept in the same table as used connections, but + unused ones have the tcpstate set to CLOSED. Also, connections in + TIME_WAIT are kept track of and we'll use the oldest one if no + CLOSED connections are found. Thanks to Eddie C. Dost for a very + nice algorithm for the TIME_WAIT search. */ + uip_connr = 0; + for(c = 0; c < UIP_CONNS; ++c) { + if(uip_conns[c].tcpstateflags == UIP_CLOSED) { + uip_connr = &uip_conns[c]; + break; + } + if(uip_conns[c].tcpstateflags == UIP_TIME_WAIT) { + if(uip_connr == 0 || + uip_conns[c].timer > uip_connr->timer) { + uip_connr = &uip_conns[c]; + } + } + } + + if(uip_connr == 0) { + /* All connections are used already, we drop packet and hope that + the remote end will retransmit the packet at a time when we + have more spare connections. */ + UIP_STAT(++uip_stat.tcp.syndrop); + UIP_LOG("tcp: found no unused connections."); + goto drop; + } + uip_conn = uip_connr; + + /* Fill in the necessary fields for the new connection. */ + uip_connr->rto = uip_connr->timer = UIP_RTO; + uip_connr->sa = 0; + uip_connr->sv = 4; + uip_connr->nrtx = 0; + uip_connr->lport = BUF->destport; + uip_connr->rport = BUF->srcport; + uip_ipaddr_copy(&uip_connr->ripaddr, &BUF->srcipaddr); + uip_connr->tcpstateflags = UIP_SYN_RCVD; + + uip_connr->snd_nxt[0] = iss[0]; + uip_connr->snd_nxt[1] = iss[1]; + uip_connr->snd_nxt[2] = iss[2]; + uip_connr->snd_nxt[3] = iss[3]; + uip_connr->len = 1; + + /* rcv_nxt should be the seqno from the incoming packet + 1. */ + uip_connr->rcv_nxt[3] = BUF->seqno[3]; + uip_connr->rcv_nxt[2] = BUF->seqno[2]; + uip_connr->rcv_nxt[1] = BUF->seqno[1]; + uip_connr->rcv_nxt[0] = BUF->seqno[0]; + uip_add_rcv_nxt(1); + + /* Parse the TCP MSS option, if present. */ + if((BUF->tcpoffset & 0xf0) > 0x50) { + for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) { + opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c]; + if(opt == TCP_OPT_END) { + /* End of options. */ + break; + } else if(opt == TCP_OPT_NOOP) { + ++c; + /* NOP option. */ + } else if(opt == TCP_OPT_MSS && + uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) { + /* An MSS option with the right option length. */ + tmp16 = ((u16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | + (u16_t)uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + c]; + uip_connr->initialmss = uip_connr->mss = + tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16; + + /* And we are done processing options. */ + break; + } else { + /* All other options have a length field, so that we easily + can skip past them. */ + if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) { + /* If the length field is zero, the options are malformed + and we don't process them further. */ + break; + } + c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c]; + } + } + } + + /* Our response will be a SYNACK. */ +#if UIP_ACTIVE_OPEN + tcp_send_synack: + BUF->flags = TCP_ACK; + + tcp_send_syn: + BUF->flags |= TCP_SYN; +#else /* UIP_ACTIVE_OPEN */ + tcp_send_synack: + BUF->flags = TCP_SYN | TCP_ACK; +#endif /* UIP_ACTIVE_OPEN */ + + /* We send out the TCP Maximum Segment Size option with our + SYNACK. */ + BUF->optdata[0] = TCP_OPT_MSS; + BUF->optdata[1] = TCP_OPT_MSS_LEN; + BUF->optdata[2] = (UIP_TCP_MSS) / 256; + BUF->optdata[3] = (UIP_TCP_MSS) & 255; + uip_len = UIP_IPTCPH_LEN + TCP_OPT_MSS_LEN; + BUF->tcpoffset = ((UIP_TCPH_LEN + TCP_OPT_MSS_LEN) / 4) << 4; + goto tcp_send; + + /* This label will be jumped to if we found an active connection. */ + found: + uip_conn = uip_connr; + uip_flags = 0; + /* We do a very naive form of TCP reset processing; we just accept + any RST and kill our connection. We should in fact check if the + sequence number of this reset is within our advertised window + before we accept the reset. */ + if(BUF->flags & TCP_RST) { + uip_connr->tcpstateflags = UIP_CLOSED; + UIP_LOG("tcp: got reset, aborting connection."); + uip_flags = UIP_ABORT; + UIP_APPCALL(); + goto drop; + } + /* Calculate the length of the data, if the application has sent + any data to us. */ + c = (BUF->tcpoffset >> 4) << 2; + /* uip_len will contain the length of the actual TCP data. This is + calculated by subtracing the length of the TCP header (in + c) and the length of the IP header (20 bytes). */ + uip_len = uip_len - c - UIP_IPH_LEN; + + /* First, check if the sequence number of the incoming packet is + what we're expecting next. If not, we send out an ACK with the + correct numbers in. */ + if(!(((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) && + ((BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)))) { + if((uip_len > 0 || ((BUF->flags & (TCP_SYN | TCP_FIN)) != 0)) && + (BUF->seqno[0] != uip_connr->rcv_nxt[0] || + BUF->seqno[1] != uip_connr->rcv_nxt[1] || + BUF->seqno[2] != uip_connr->rcv_nxt[2] || + BUF->seqno[3] != uip_connr->rcv_nxt[3])) { + goto tcp_send_ack; + } + } + + /* Next, check if the incoming segment acknowledges any outstanding + data. If so, we update the sequence number, reset the length of + the outstanding data, calculate RTT estimations, and reset the + retransmission timer. */ + if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) { + uip_add32(uip_connr->snd_nxt, uip_connr->len); + + if(BUF->ackno[0] == uip_acc32[0] && + BUF->ackno[1] == uip_acc32[1] && + BUF->ackno[2] == uip_acc32[2] && + BUF->ackno[3] == uip_acc32[3]) { + /* Update sequence number. */ + uip_connr->snd_nxt[0] = uip_acc32[0]; + uip_connr->snd_nxt[1] = uip_acc32[1]; + uip_connr->snd_nxt[2] = uip_acc32[2]; + uip_connr->snd_nxt[3] = uip_acc32[3]; + + /* Do RTT estimation, unless we have done retransmissions. */ + if(uip_connr->nrtx == 0) { + signed char m; + m = uip_connr->rto - uip_connr->timer; + /* This is taken directly from VJs original code in his paper */ + m = m - (uip_connr->sa >> 3); + uip_connr->sa += m; + if(m < 0) { + m = -m; + } + m = m - (uip_connr->sv >> 2); + uip_connr->sv += m; + uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv; + + } + /* Set the acknowledged flag. */ + uip_flags = UIP_ACKDATA; + /* Reset the retransmission timer. */ + uip_connr->timer = uip_connr->rto; + + /* Reset length of outstanding data. */ + uip_connr->len = 0; + } + + } + + /* Do different things depending on in what state the connection is. */ + switch(uip_connr->tcpstateflags & UIP_TS_MASK) { + /* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not + implemented, since we force the application to close when the + peer sends a FIN (hence the application goes directly from + ESTABLISHED to LAST_ACK). */ + case UIP_SYN_RCVD: + /* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and + we are waiting for an ACK that acknowledges the data we sent + out the last time. Therefore, we want to have the UIP_ACKDATA + flag set. If so, we enter the ESTABLISHED state. */ + if(uip_flags & UIP_ACKDATA) { + uip_connr->tcpstateflags = UIP_ESTABLISHED; + uip_flags = UIP_CONNECTED; + uip_connr->len = 0; + if(uip_len > 0) { + uip_flags |= UIP_NEWDATA; + uip_add_rcv_nxt(uip_len); + } + uip_slen = 0; + UIP_APPCALL(); + goto appsend; + } + goto drop; +#if UIP_ACTIVE_OPEN + case UIP_SYN_SENT: + /* In SYN_SENT, we wait for a SYNACK that is sent in response to + our SYN. The rcv_nxt is set to sequence number in the SYNACK + plus one, and we send an ACK. We move into the ESTABLISHED + state. */ + if((uip_flags & UIP_ACKDATA) && + (BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)) { + + /* Parse the TCP MSS option, if present. */ + if((BUF->tcpoffset & 0xf0) > 0x50) { + for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) { + opt = uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + c]; + if(opt == TCP_OPT_END) { + /* End of options. */ + break; + } else if(opt == TCP_OPT_NOOP) { + ++c; + /* NOP option. */ + } else if(opt == TCP_OPT_MSS && + uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) { + /* An MSS option with the right option length. */ + tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | + uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c]; + uip_connr->initialmss = + uip_connr->mss = tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16; + + /* And we are done processing options. */ + break; + } else { + /* All other options have a length field, so that we easily + can skip past them. */ + if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) { + /* If the length field is zero, the options are malformed + and we don't process them further. */ + break; + } + c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c]; + } + } + } + uip_connr->tcpstateflags = UIP_ESTABLISHED; + uip_connr->rcv_nxt[0] = BUF->seqno[0]; + uip_connr->rcv_nxt[1] = BUF->seqno[1]; + uip_connr->rcv_nxt[2] = BUF->seqno[2]; + uip_connr->rcv_nxt[3] = BUF->seqno[3]; + uip_add_rcv_nxt(1); + uip_flags = UIP_CONNECTED | UIP_NEWDATA; + uip_connr->len = 0; + uip_len = 0; + uip_slen = 0; + UIP_APPCALL(); + goto appsend; + } + /* Inform the application that the connection failed */ + uip_flags = UIP_ABORT; + UIP_APPCALL(); + /* The connection is closed after we send the RST */ + uip_conn->tcpstateflags = UIP_CLOSED; + goto reset; +#endif /* UIP_ACTIVE_OPEN */ + + case UIP_ESTABLISHED: + /* In the ESTABLISHED state, we call upon the application to feed + data into the uip_buf. If the UIP_ACKDATA flag is set, the + application should put new data into the buffer, otherwise we are + retransmitting an old segment, and the application should put that + data into the buffer. + + If the incoming packet is a FIN, we should close the connection on + this side as well, and we send out a FIN and enter the LAST_ACK + state. We require that there is no outstanding data; otherwise the + sequence numbers will be screwed up. */ + + if(BUF->flags & TCP_FIN && !(uip_connr->tcpstateflags & UIP_STOPPED)) { + if(uip_outstanding(uip_connr)) { + goto drop; + } + uip_add_rcv_nxt(1 + uip_len); + uip_flags |= UIP_CLOSE; + if(uip_len > 0) { + uip_flags |= UIP_NEWDATA; + } + UIP_APPCALL(); + uip_connr->len = 1; + uip_connr->tcpstateflags = UIP_LAST_ACK; + uip_connr->nrtx = 0; + tcp_send_finack: + BUF->flags = TCP_FIN | TCP_ACK; + goto tcp_send_nodata; + } + + /* Check the URG flag. If this is set, the segment carries urgent + data that we must pass to the application. */ + if((BUF->flags & TCP_URG) != 0) { +#if UIP_URGDATA > 0 + uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1]; + if(uip_urglen > uip_len) { + /* There is more urgent data in the next segment to come. */ + uip_urglen = uip_len; + } + uip_add_rcv_nxt(uip_urglen); + uip_len -= uip_urglen; + uip_urgdata = uip_appdata; + uip_appdata += uip_urglen; + } else { + uip_urglen = 0; +#else /* UIP_URGDATA > 0 */ + uip_appdata = ((char *)uip_appdata) + ((BUF->urgp[0] << 8) | BUF->urgp[1]); + uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1]; +#endif /* UIP_URGDATA > 0 */ + } + + /* If uip_len > 0 we have TCP data in the packet, and we flag this + by setting the UIP_NEWDATA flag and update the sequence number + we acknowledge. If the application has stopped the dataflow + using uip_stop(), we must not accept any data packets from the + remote host. */ + if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) { + uip_flags |= UIP_NEWDATA; + uip_add_rcv_nxt(uip_len); + } + + /* Check if the available buffer space advertised by the other end + is smaller than the initial MSS for this connection. If so, we + set the current MSS to the window size to ensure that the + application does not send more data than the other end can + handle. + + If the remote host advertises a zero window, we set the MSS to + the initial MSS so that the application will send an entire MSS + of data. This data will not be acknowledged by the receiver, + and the application will retransmit it. This is called the + "persistent timer" and uses the retransmission mechanism. + */ + tmp16 = ((u16_t)BUF->wnd[0] << 8) + (u16_t)BUF->wnd[1]; + if(tmp16 > uip_connr->initialmss || + tmp16 == 0) { + tmp16 = uip_connr->initialmss; + } + uip_connr->mss = tmp16; + + /* If this packet constitutes an ACK for outstanding data (flagged + by the UIP_ACKDATA flag, we should call the application since it + might want to send more data. If the incoming packet had data + from the peer (as flagged by the UIP_NEWDATA flag), the + application must also be notified. + + When the application is called, the global variable uip_len + contains the length of the incoming data. The application can + access the incoming data through the global pointer + uip_appdata, which usually points UIP_IPTCPH_LEN + UIP_LLH_LEN + bytes into the uip_buf array. + + If the application wishes to send any data, this data should be + put into the uip_appdata and the length of the data should be + put into uip_len. If the application don't have any data to + send, uip_len must be set to 0. */ + if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) { + uip_slen = 0; + UIP_APPCALL(); + + appsend: + + if(uip_flags & UIP_ABORT) { + uip_slen = 0; + uip_connr->tcpstateflags = UIP_CLOSED; + BUF->flags = TCP_RST | TCP_ACK; + goto tcp_send_nodata; + } + + if(uip_flags & UIP_CLOSE) { + uip_slen = 0; + uip_connr->len = 1; + uip_connr->tcpstateflags = UIP_FIN_WAIT_1; + uip_connr->nrtx = 0; + BUF->flags = TCP_FIN | TCP_ACK; + goto tcp_send_nodata; + } + + /* If uip_slen > 0, the application has data to be sent. */ + if(uip_slen > 0) { + + /* If the connection has acknowledged data, the contents of + the ->len variable should be discarded. */ + if((uip_flags & UIP_ACKDATA) != 0) { + uip_connr->len = 0; + } + + /* If the ->len variable is non-zero the connection has + already data in transit and cannot send anymore right + now. */ + if(uip_connr->len == 0) { + + /* The application cannot send more than what is allowed by + the mss (the minumum of the MSS and the available + window). */ + if(uip_slen > uip_connr->mss) { + uip_slen = uip_connr->mss; + } + + /* Remember how much data we send out now so that we know + when everything has been acknowledged. */ + uip_connr->len = uip_slen; + } else { + + /* If the application already had unacknowledged data, we + make sure that the application does not send (i.e., + retransmit) out more than it previously sent out. */ + uip_slen = uip_connr->len; + } + } + uip_connr->nrtx = 0; + apprexmit: + uip_appdata = uip_sappdata; + + /* If the application has data to be sent, or if the incoming + packet had new data in it, we must send out a packet. */ + if(uip_slen > 0 && uip_connr->len > 0) { + /* Add the length of the IP and TCP headers. */ + uip_len = uip_connr->len + UIP_TCPIP_HLEN; + /* We always set the ACK flag in response packets. */ + BUF->flags = TCP_ACK | TCP_PSH; + /* Send the packet. */ + goto tcp_send_noopts; + } + /* If there is no data to send, just send out a pure ACK if + there is newdata. */ + if(uip_flags & UIP_NEWDATA) { + uip_len = UIP_TCPIP_HLEN; + BUF->flags = TCP_ACK; + goto tcp_send_noopts; + } + } + goto drop; + case UIP_LAST_ACK: + /* We can close this connection if the peer has acknowledged our + FIN. This is indicated by the UIP_ACKDATA flag. */ + if(uip_flags & UIP_ACKDATA) { + uip_connr->tcpstateflags = UIP_CLOSED; + uip_flags = UIP_CLOSE; + UIP_APPCALL(); + } + break; + + case UIP_FIN_WAIT_1: + /* The application has closed the connection, but the remote host + hasn't closed its end yet. Thus we do nothing but wait for a + FIN from the other side. */ + if(uip_len > 0) { + uip_add_rcv_nxt(uip_len); + } + if(BUF->flags & TCP_FIN) { + if(uip_flags & UIP_ACKDATA) { + uip_connr->tcpstateflags = UIP_TIME_WAIT; + uip_connr->timer = 0; + uip_connr->len = 0; + } else { + uip_connr->tcpstateflags = UIP_CLOSING; + } + uip_add_rcv_nxt(1); + uip_flags = UIP_CLOSE; + UIP_APPCALL(); + goto tcp_send_ack; + } else if(uip_flags & UIP_ACKDATA) { + uip_connr->tcpstateflags = UIP_FIN_WAIT_2; + uip_connr->len = 0; + goto drop; + } + if(uip_len > 0) { + goto tcp_send_ack; + } + goto drop; + + case UIP_FIN_WAIT_2: + if(uip_len > 0) { + uip_add_rcv_nxt(uip_len); + } + if(BUF->flags & TCP_FIN) { + uip_connr->tcpstateflags = UIP_TIME_WAIT; + uip_connr->timer = 0; + uip_add_rcv_nxt(1); + uip_flags = UIP_CLOSE; + UIP_APPCALL(); + goto tcp_send_ack; + } + if(uip_len > 0) { + goto tcp_send_ack; + } + goto drop; + + case UIP_TIME_WAIT: + goto tcp_send_ack; + + case UIP_CLOSING: + if(uip_flags & UIP_ACKDATA) { + uip_connr->tcpstateflags = UIP_TIME_WAIT; + uip_connr->timer = 0; + } + } + goto drop; + + /* We jump here when we are ready to send the packet, and just want + to set the appropriate TCP sequence numbers in the TCP header. */ + tcp_send_ack: + BUF->flags = TCP_ACK; + + tcp_send_nodata: + uip_len = UIP_IPTCPH_LEN; + + tcp_send_noopts: + BUF->tcpoffset = (UIP_TCPH_LEN / 4) << 4; + + /* We're done with the input processing. We are now ready to send a + reply. Our job is to fill in all the fields of the TCP and IP + headers before calculating the checksum and finally send the + packet. */ + tcp_send: + BUF->ackno[0] = uip_connr->rcv_nxt[0]; + BUF->ackno[1] = uip_connr->rcv_nxt[1]; + BUF->ackno[2] = uip_connr->rcv_nxt[2]; + BUF->ackno[3] = uip_connr->rcv_nxt[3]; + + BUF->seqno[0] = uip_connr->snd_nxt[0]; + BUF->seqno[1] = uip_connr->snd_nxt[1]; + BUF->seqno[2] = uip_connr->snd_nxt[2]; + BUF->seqno[3] = uip_connr->snd_nxt[3]; + + BUF->proto = UIP_PROTO_TCP; + + BUF->srcport = uip_connr->lport; + BUF->destport = uip_connr->rport; + + uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr); + uip_ipaddr_copy(&BUF->destipaddr, &uip_connr->ripaddr); + + if(uip_connr->tcpstateflags & UIP_STOPPED) { + /* If the connection has issued uip_stop(), we advertise a zero + window so that the remote host will stop sending data. */ + BUF->wnd[0] = BUF->wnd[1] = 0; + } else { + BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8); + BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff); + } + + tcp_send_noconn: + BUF->ttl = UIP_TTL; +#if UIP_CONF_IPV6 + /* For IPv6, the IP length field does not include the IPv6 IP header + length. */ + BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8); + BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff); +#else /* UIP_CONF_IPV6 */ + BUF->len[0] = (uip_len >> 8); + BUF->len[1] = (uip_len & 0xff); +#endif /* UIP_CONF_IPV6 */ + + BUF->urgp[0] = BUF->urgp[1] = 0; + + /* Calculate TCP checksum. */ + BUF->tcpchksum = 0; + BUF->tcpchksum = ~(uip_tcpchksum()); + + ip_send_nolen: +#if UIP_CONF_IPV6 + BUF->vtc = 0x60; + BUF->tcflow = 0x00; + BUF->flow = 0x00; +#else /* UIP_CONF_IPV6 */ + BUF->vhl = 0x45; + BUF->tos = 0; + BUF->ipoffset[0] = BUF->ipoffset[1] = 0; + ++ipid; + BUF->ipid[0] = ipid >> 8; + BUF->ipid[1] = ipid & 0xff; + /* Calculate IP checksum. */ + BUF->ipchksum = 0; + BUF->ipchksum = ~(uip_ipchksum()); + DEBUG_PRINTF("uip ip_send_nolen: checksum 0x%04x\n", uip_ipchksum()); +#endif /* UIP_CONF_IPV6 */ + UIP_STAT(++uip_stat.tcp.sent); +#if UIP_CONF_IPV6 + send: +#endif /* UIP_CONF_IPV6 */ + DEBUG_PRINTF("Sending packet with length %d (%d)\n", uip_len, + (BUF->len[0] << 8) | BUF->len[1]); + + UIP_STAT(++uip_stat.ip.sent); + /* Return and let the caller do the actual transmission. */ + uip_flags = 0; + return; + + drop: + uip_len = 0; + uip_flags = 0; + return; +} +/*---------------------------------------------------------------------------*/ +u16_t +htons(u16_t val) +{ + return HTONS(val); +} + +u32_t +htonl(u32_t val) +{ + return HTONL(val); +} +/*---------------------------------------------------------------------------*/ +void +uip_send(const void *data, int len) +{ + int copylen; +#define MIN(a,b) ((a) < (b)? (a): (b)) + copylen = MIN(len, UIP_BUFSIZE - UIP_LLH_LEN - UIP_TCPIP_HLEN - + (int)((char *)uip_sappdata - (char *)&uip_buf[UIP_LLH_LEN + UIP_TCPIP_HLEN])); + if(copylen > 0) { + uip_slen = copylen; + if(data != uip_sappdata) { + memcpy(uip_sappdata, (data), uip_slen); + } + } +} +/*---------------------------------------------------------------------------*/ +/** @} */ +#endif /* UIP_CONF_IPV6 */ + |