| /* |
| * Copyright (c) 2001-2002, 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. All advertising materials mentioning features or use of this software |
| * must display the following acknowledgement: |
| * This product includes software developed by Adam Dunkels. |
| * 4. 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 1.9 2003/08/21 22:26:57 adamdunkels Exp $ |
| * |
| */ |
| |
| /* |
| This is a small implementation of the IP and TCP protocols (as well as |
| some basic ICMP stuff). The implementation couples the IP, TCP and the |
| application layers very tightly. To keep the size of the compiled code |
| down, this code also features heavy usage of the goto statement. |
| |
| 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 upon 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, 40 bytes from the start of the buffer. 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_arch.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 u16_t uip_hostaddr[2] = |
| {HTONS((UIP_IPADDR0 << 8) | UIP_IPADDR1), |
| HTONS((UIP_IPADDR2 << 8) | UIP_IPADDR3)}; |
| #else |
| u16_t uip_hostaddr[2]; |
| #endif /* UIP_FIXEDADDR */ |
| |
| u8_t uip_buf[UIP_BUFSIZE+2]; /* The packet buffer that contains |
| incoming packets. */ |
| volatile u8_t *uip_appdata; /* The uip_appdata pointer points to |
| application data. */ |
| #if UIP_URGDATA > 0 |
| volatile u8_t *uip_urgdata; /* The uip_urgdata pointer points to |
| urgent data (out-of-band data), if |
| present. */ |
| volatile u8_t uip_urglen, uip_surglen; |
| #endif /* UIP_URGDATA > 0 */ |
| |
| #if UIP_BUFSIZE > 255 |
| volatile u16_t uip_len, uip_slen; |
| /* The uip_len is either 8 or 16 bits, |
| depending on the maximum packet |
| size. */ |
| #else |
| volatile u8_t uip_len, uip_slen; |
| #endif /* UIP_BUFSIZE > 255 */ |
| |
| volatile 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 |
| listning 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. */ |
| |
| static u8_t iss[4]; /* The iss variable is used for the TCP |
| initial sequence number. */ |
| |
| #if UIP_ACTIVE_OPEN |
| /* XXX static */ u16_t lastport; /* Keeps track of the last port used for |
| a new connection. */ |
| #endif /* UIP_ACTIVE_OPEN */ |
| |
| /* Temporary variables. */ |
| volatile u8_t uip_acc32[4]; |
| static u8_t c, opt; |
| static u16_t tmpport; |
| |
| /* 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 ICMP_ECHO_REPLY 0 |
| #define ICMP_ECHO 8 |
| |
| /* Macros. */ |
| #define BUF ((uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN]) |
| #define FBUF ((uip_tcpip_hdr *)&uip_reassbuf[0]) |
| #define ICMPBUF ((uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN]) |
| #define UDPBUF ((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 */ |
| |
| /*-----------------------------------------------------------------------------------*/ |
| 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 = 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(u16_t *ripaddr, u16_t rport) |
| { |
| register struct uip_conn *conn, *cconn; |
| |
| /* Find an unused local port. */ |
| again: |
| ++lastport; |
| |
| if(lastport >= 32000) { |
| lastport = 4096; |
| } |
| |
| for(c = 0; c < UIP_CONNS; ++c) { |
| conn = &uip_conns[c]; |
| if(conn->tcpstateflags != CLOSED && |
| conn->lport == lastport) { |
| goto again; |
| } |
| } |
| |
| |
| conn = 0; |
| for(c = 0; c < UIP_CONNS; ++c) { |
| cconn = &uip_conns[c]; |
| if(cconn->tcpstateflags == CLOSED) { |
| conn = cconn; |
| break; |
| } |
| if(cconn->tcpstateflags == TIME_WAIT) { |
| if(conn == 0 || |
| cconn->timer > uip_conn->timer) { |
| conn = cconn; |
| } |
| } |
| } |
| |
| if(conn == 0) { |
| return 0; |
| } |
| |
| conn->tcpstateflags = 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->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->lport = HTONS(lastport); |
| conn->rport = HTONS(rport); |
| conn->ripaddr[0] = ripaddr[0]; |
| conn->ripaddr[1] = ripaddr[1]; |
| |
| return conn; |
| } |
| #endif /* UIP_ACTIVE_OPEN */ |
| /*-----------------------------------------------------------------------------------*/ |
| #if UIP_UDP |
| struct uip_udp_conn * |
| uip_udp_new(u16_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 == 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 = HTONS(rport); |
| conn->ripaddr[0] = ripaddr[0]; |
| conn->ripaddr[1] = ripaddr[1]; |
| |
| 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] = htons(port); |
| return; |
| } |
| } |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| #define UIP_REASSEMBLY 0 |
| |
| #define UIP_REASS_MAXAGE 10 |
| |
| #if UIP_REASSEMBLY |
| #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_HLEN 20 |
| #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) { |
| bcopy(&BUF->vhl, uip_reassbuf, IP_HLEN); |
| uip_reasstmr = UIP_REASS_MAXAGE; |
| uip_reassflags = 0; |
| /* Clear the bitmap. */ |
| bzero(uip_reassbitmap, 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->destipaddr[1] == FBUF->destipaddr[1] && |
| BUF->srcipaddr[0] == FBUF->srcipaddr[0] && |
| BUF->destipaddr[1] == FBUF->destipaddr[1] && |
| BUF->ipid == FBUF->ipid) { |
| |
| 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. */ |
| bcopy(BUF + (BUF->vhl & 0x0f) * 4, |
| &uip_reassbuf[IP_HLEN + offset], 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 inbetween 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; |
| bcopy(FBUF, BUF, uip_reasslen); |
| |
| /* Pretend to be a "normal" (i.e., not fragmented) IP packet |
| from now on. */ |
| BUF->ipoffset[0] = BUF->ipoffset[1] = 0; |
| BUF->ipchksum = 0; |
| BUF->ipchksum = ~(uip_ipchksum()); |
| |
| |
| |
| return uip_reasslen; |
| } |
| } |
| |
| nullreturn: |
| return 0; |
| } |
| #endif /* IP_REASSEMBLY */ |
| /*-----------------------------------------------------------------------------------*/ |
| void |
| uip_process(u8_t flag) |
| { |
| register struct uip_conn *uip_connr = uip_conn; |
| /*#define uip_connr uip_conn*/ |
| |
| uip_appdata = &uip_buf[40 + UIP_LLH_LEN]; |
| |
| |
| /* Check if we were invoked because of the perodic timer fireing. */ |
| if(flag == UIP_TIMER) { |
| /* Increase the initial sequence number. */ |
| if(++iss[3] == 0) { |
| if(++iss[2] == 0) { |
| if(++iss[1] == 0) { |
| ++iss[0]; |
| } |
| } |
| } |
| uip_len = 0; |
| if(uip_connr->tcpstateflags == TIME_WAIT || |
| uip_connr->tcpstateflags == FIN_WAIT_2) { |
| ++(uip_connr->timer); |
| if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) { |
| uip_connr->tcpstateflags = CLOSED; |
| } |
| } else if(uip_connr->tcpstateflags != 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)) { |
| --(uip_connr->timer); |
| if(uip_connr->timer == 0) { |
| if(uip_connr->nrtx == UIP_MAXRTX || |
| ((uip_connr->tcpstateflags == SYN_SENT || |
| uip_connr->tcpstateflags == SYN_RCVD) && |
| uip_connr->nrtx == UIP_MAXSYNRTX)) { |
| uip_connr->tcpstateflags = 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 backoff. */ |
| 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 & TS_MASK) { |
| case SYN_RCVD: |
| /* In the SYN_RCVD state, we should retransmit our |
| SYNACK. */ |
| goto tcp_send_synack; |
| |
| #if UIP_ACTIVE_OPEN |
| case SYN_SENT: |
| /* In the SYN_SENT state, we retransmit out SYN. */ |
| BUF->flags = 0; |
| goto tcp_send_syn; |
| #endif /* UIP_ACTIVE_OPEN */ |
| |
| case 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_len = 0; |
| uip_slen = 0; |
| uip_flags = UIP_REXMIT; |
| UIP_APPCALL(); |
| goto apprexmit; |
| |
| case FIN_WAIT_1: |
| case CLOSING: |
| case LAST_ACK: |
| /* In all these states we should retransmit a FINACK. */ |
| goto tcp_send_finack; |
| |
| } |
| } |
| } else if((uip_connr->tcpstateflags & TS_MASK) == ESTABLISHED) { |
| /* If there was no need for a retransmission, we poll the |
| application for new data. */ |
| uip_len = 0; |
| 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_appdata = &uip_buf[UIP_LLH_LEN + 28]; |
| 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 IPv4 input header processing code. */ |
| |
| /* 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; |
| } |
| |
| /* Check the size of the packet. If the size reported to us in |
| uip_len doesn't match the size reported in the IP header, there |
| has been a transmission error and we drop the packet. */ |
| |
| #if UIP_BUFSIZE > 255 |
| if(BUF->len[0] != (uip_len >> 8)) { /* IP length, high byte. */ |
| uip_len = (uip_len & 0xff) | (BUF->len[0] << 8); |
| } |
| if(BUF->len[1] != (uip_len & 0xff)) { /* IP length, low byte. */ |
| uip_len = (uip_len & 0xff00) | BUF->len[1]; |
| } |
| #else |
| if(BUF->len[0] != 0) { /* IP length, high byte. */ |
| UIP_STAT(++uip_stat.ip.drop); |
| UIP_STAT(++uip_stat.ip.hblenerr); |
| UIP_LOG("ip: invalid length, high byte."); |
| goto drop; |
| } |
| if(BUF->len[1] != uip_len) { /* IP length, low byte. */ |
| uip_len = BUF->len[1]; |
| } |
| #endif /* UIP_BUFSIZE > 255 */ |
| |
| if(BUF->ipoffset[0] & 0x3f) { /* We don't allow IP fragments. */ |
| UIP_STAT(++uip_stat.ip.drop); |
| UIP_STAT(++uip_stat.ip.fragerr); |
| UIP_LOG("ip: fragment dropped."); |
| goto drop; |
| } |
| |
| /* 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 |
| if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) { |
| 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 */ |
| |
| /* Check if the packet is destined for our IP address. */ |
| if(BUF->destipaddr[0] != uip_hostaddr[0]) { |
| UIP_STAT(++uip_stat.ip.drop); |
| UIP_LOG("ip: packet not for us."); |
| goto drop; |
| } |
| if(BUF->destipaddr[1] != uip_hostaddr[1]) { |
| UIP_STAT(++uip_stat.ip.drop); |
| UIP_LOG("ip: packet not for us."); |
| goto drop; |
| } |
| |
| 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; |
| } |
| |
| if(BUF->proto == UIP_PROTO_TCP) /* Check for TCP packet. If so, jump |
| to the tcp_input label. */ |
| goto tcp_input; |
| |
| #if UIP_UDP |
| if(BUF->proto == UIP_PROTO_UDP) |
| goto udp_input; |
| #endif /* UIP_UDP */ |
| |
| 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; |
| } |
| |
| icmp_input: |
| 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 |
| ourself. */ |
| #if UIP_PINGADDRCONF |
| if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) { |
| uip_hostaddr[0] = BUF->destipaddr[0]; |
| uip_hostaddr[1] = BUF->destipaddr[1]; |
| } |
| #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. */ |
| tmpport = BUF->destipaddr[0]; |
| BUF->destipaddr[0] = BUF->srcipaddr[0]; |
| BUF->srcipaddr[0] = tmpport; |
| tmpport = BUF->destipaddr[1]; |
| BUF->destipaddr[1] = BUF->srcipaddr[1]; |
| BUF->srcipaddr[1] = tmpport; |
| |
| UIP_STAT(++uip_stat.icmp.sent); |
| goto send; |
| |
| /* End of IPv4 input header processing code. */ |
| |
| |
| #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 |
| if(uip_udpchksum() != 0xffff) { |
| UIP_STAT(++uip_stat.udp.drop); |
| UIP_STAT(++uip_stat.udp.chkerr); |
| UIP_LOG("udp: bad checksum."); |
| goto drop; |
| } |
| #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(uip_udp_conn->lport != 0 && |
| UDPBUF->destport == uip_udp_conn->lport && |
| (uip_udp_conn->rport == 0 || |
| UDPBUF->srcport == uip_udp_conn->rport) && |
| BUF->srcipaddr[0] == uip_udp_conn->ripaddr[0] && |
| BUF->srcipaddr[1] == uip_udp_conn->ripaddr[1]) { |
| goto udp_found; |
| } |
| } |
| goto drop; |
| |
| udp_found: |
| uip_len = uip_len - 28; |
| uip_appdata = &uip_buf[UIP_LLH_LEN + 28]; |
| uip_flags = UIP_NEWDATA; |
| uip_slen = 0; |
| UIP_UDP_APPCALL(); |
| udp_send: |
| if(uip_slen == 0) { |
| goto drop; |
| } |
| uip_len = uip_slen + 28; |
| |
| #if UIP_BUFSIZE > 255 |
| BUF->len[0] = (uip_len >> 8); |
| BUF->len[1] = (uip_len & 0xff); |
| #else |
| BUF->len[0] = 0; |
| BUF->len[1] = uip_len; |
| #endif /* UIP_BUFSIZE > 255 */ |
| BUF->proto = UIP_PROTO_UDP; |
| |
| UDPBUF->udplen = HTONS(uip_slen + 8); |
| UDPBUF->udpchksum = 0; |
| #if UIP_UDP_CHECKSUMS |
| /* Calculate UDP checksum. */ |
| UDPBUF->udpchksum = ~(uip_udpchksum()); |
| if(UDPBUF->udpchksum == 0) { |
| UDPBUF->udpchksum = 0xffff; |
| } |
| #endif /* UIP_UDP_CHECKSUMS */ |
| |
| BUF->srcport = uip_udp_conn->lport; |
| BUF->destport = uip_udp_conn->rport; |
| |
| BUF->srcipaddr[0] = uip_hostaddr[0]; |
| BUF->srcipaddr[1] = uip_hostaddr[1]; |
| BUF->destipaddr[0] = uip_udp_conn->ripaddr[0]; |
| BUF->destipaddr[1] = uip_udp_conn->ripaddr[1]; |
| |
| uip_appdata = &uip_buf[UIP_LLH_LEN + 40]; |
| 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]; ++uip_connr) { |
| if(uip_connr->tcpstateflags != CLOSED && |
| BUF->destport == uip_connr->lport && |
| BUF->srcport == uip_connr->rport && |
| BUF->srcipaddr[0] == uip_connr->ripaddr[0] && |
| BUF->srcipaddr[1] == uip_connr->ripaddr[1]) { |
| 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; |
| |
| tmpport = BUF->destport; |
| /* Next, check listening connections. */ |
| for(c = 0; c < UIP_LISTENPORTS; ++c) { |
| if(tmpport == 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 = 40; |
| 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. */ |
| tmpport = BUF->srcport; |
| BUF->srcport = BUF->destport; |
| BUF->destport = tmpport; |
| |
| /* Swap IP addresses. */ |
| tmpport = BUF->destipaddr[0]; |
| BUF->destipaddr[0] = BUF->srcipaddr[0]; |
| BUF->srcipaddr[0] = tmpport; |
| tmpport = BUF->destipaddr[1]; |
| BUF->destipaddr[1] = BUF->srcipaddr[1]; |
| BUF->srcipaddr[1] = tmpport; |
| |
| |
| /* 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 avaliable. 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 == CLOSED) { |
| uip_connr = &uip_conns[c]; |
| break; |
| } |
| if(uip_conns[c].tcpstateflags == 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->timer = UIP_RTO; |
| uip_connr->nrtx = 0; |
| uip_connr->lport = BUF->destport; |
| uip_connr->rport = BUF->srcport; |
| uip_connr->ripaddr[0] = BUF->srcipaddr[0]; |
| uip_connr->ripaddr[1] = BUF->srcipaddr[1]; |
| uip_connr->tcpstateflags = 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 == 0x00) { |
| /* End of options. */ |
| break; |
| } else if(opt == 0x01) { |
| ++c; |
| /* NOP option. */ |
| } else if(opt == 0x02 && |
| uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) { |
| /* An MSS option with the right option length. */ |
| tmpport = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | |
| uip_buf[40 + UIP_LLH_LEN + 3 + c]; |
| uip_connr->mss = tmpport > UIP_TCP_MSS? UIP_TCP_MSS: tmpport; |
| |
| /* 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] = 2; |
| BUF->optdata[1] = 4; |
| BUF->optdata[2] = (UIP_TCP_MSS) / 256; |
| BUF->optdata[3] = (UIP_TCP_MSS) & 255; |
| uip_len = 44; |
| BUF->tcpoffset = 6 << 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 wihtin our advertised window |
| before we accept the reset. */ |
| if(BUF->flags & TCP_RST) { |
| uip_connr->tcpstateflags = CLOSED; |
| UIP_LOG("tcp: got reset, aborting connection."); |
| uip_flags = UIP_ABORT; |
| UIP_APPCALL(); |
| goto drop; |
| } |
| /* Calculated 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 - 20; |
| |
| /* 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_len > 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_RTO << (uip_connr->nrtx > 4? 4: uip_connr->nrtx)) - 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 length of the outstanding data. */ |
| uip_connr->len = 0; |
| /* Reset the retransmission timer. */ |
| uip_connr->timer = UIP_RTO; |
| } |
| |
| } |
| |
| /* Do different things depending on in what state the connection is. */ |
| switch(uip_connr->tcpstateflags & 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 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 = ESTABLISHED; |
| uip_flags = UIP_CONNECTED; |
| 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 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_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[40 + UIP_LLH_LEN + c]; |
| if(opt == 0x00) { |
| /* End of options. */ |
| break; |
| } else if(opt == 0x01) { |
| ++c; |
| /* NOP option. */ |
| } else if(opt == 0x02 && |
| uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) { |
| /* An MSS option with the right option length. */ |
| tmpport = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | |
| uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c]; |
| uip_connr->mss = tmpport > UIP_TCP_MSS? UIP_TCP_MSS: tmpport; |
| |
| /* 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 = 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_len = 0; |
| uip_slen = 0; |
| UIP_APPCALL(); |
| goto appsend; |
| } |
| goto reset; |
| #endif /* UIP_ACTIVE_OPEN */ |
| |
| case 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) { |
| 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 = 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) { |
| #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; |
| #endif /* UIP_URGDATA > 0 */ |
| uip_appdata += (BUF->urgp[0] << 8) | BUF->urgp[1]; |
| uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1]; |
| } |
| |
| |
| /* 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); |
| } |
| |
| |
| /* 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 40 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 = 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 = 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. We |
| cannot send data if the application already has outstanding |
| data. */ |
| if(uip_slen > 0 && |
| !uip_outstanding(uip_connr)) { |
| uip_connr->nrtx = 0; |
| uip_connr->len = uip_slen; |
| } else { |
| uip_connr->nrtx = 0; |
| uip_slen = uip_connr->len; |
| } |
| apprexmit: |
| /* 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 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 = CLOSED; |
| uip_flags = UIP_CLOSE; |
| UIP_APPCALL(); |
| } |
| break; |
| |
| case 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 = TIME_WAIT; |
| uip_connr->timer = 0; |
| uip_connr->len = 0; |
| } else { |
| uip_connr->tcpstateflags = 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 = FIN_WAIT_2; |
| uip_connr->len = 0; |
| goto drop; |
| } |
| if(uip_len > 0) { |
| goto tcp_send_ack; |
| } |
| goto drop; |
| |
| case FIN_WAIT_2: |
| if(uip_len > 0) { |
| uip_add_rcv_nxt(uip_len); |
| } |
| if(BUF->flags & TCP_FIN) { |
| uip_connr->tcpstateflags = 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 TIME_WAIT: |
| goto tcp_send_ack; |
| |
| case CLOSING: |
| if(uip_flags & UIP_ACKDATA) { |
| uip_connr->tcpstateflags = 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 = 40; |
| tcp_send_noopts: |
| BUF->tcpoffset = 5 << 4; |
| tcp_send: |
| /* 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. */ |
| 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; |
| |
| BUF->srcipaddr[0] = uip_hostaddr[0]; |
| BUF->srcipaddr[1] = uip_hostaddr[1]; |
| BUF->destipaddr[0] = uip_connr->ripaddr[0]; |
| BUF->destipaddr[1] = uip_connr->ripaddr[1]; |
| |
| |
| 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 { |
| #if (UIP_TCP_MSS) > 255 |
| BUF->wnd[0] = (uip_connr->mss >> 8); |
| #else |
| BUF->wnd[0] = 0; |
| #endif /* UIP_MSS */ |
| BUF->wnd[1] = (uip_connr->mss & 0xff); |
| } |
| |
| tcp_send_noconn: |
| |
| #if UIP_BUFSIZE > 255 |
| BUF->len[0] = (uip_len >> 8); |
| BUF->len[1] = (uip_len & 0xff); |
| #else |
| BUF->len[0] = 0; |
| BUF->len[1] = uip_len; |
| #endif /* UIP_BUFSIZE > 255 */ |
| |
| /* Calculate TCP checksum. */ |
| BUF->tcpchksum = 0; |
| BUF->tcpchksum = ~(uip_tcpchksum()); |
| |
| ip_send_nolen: |
| |
| BUF->vhl = 0x45; |
| BUF->tos = 0; |
| BUF->ipoffset[0] = BUF->ipoffset[1] = 0; |
| BUF->ttl = UIP_TTL; |
| ++ipid; |
| BUF->ipid[0] = ipid >> 8; |
| BUF->ipid[1] = ipid & 0xff; |
| |
| /* Calculate IP checksum. */ |
| BUF->ipchksum = 0; |
| BUF->ipchksum = ~(uip_ipchksum()); |
| |
| UIP_STAT(++uip_stat.tcp.sent); |
| send: |
| UIP_STAT(++uip_stat.ip.sent); |
| /* Return and let the caller do the actual transmission. */ |
| return; |
| drop: |
| uip_len = 0; |
| return; |
| } |
| /*-----------------------------------------------------------------------------------*/ |
| u16_t |
| htons(u16_t val) |
| { |
| return HTONS(val); |
| } |
| /*-----------------------------------------------------------------------------------*/ |