0,0 → 1,1513 |
/** |
* \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 1.62.2.10 2003/10/07 13:23:01 adam 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" |
#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 u16_t uip_hostaddr[2] = |
{HTONS((UIP_IPADDR0 << 8) | UIP_IPADDR1), |
HTONS((UIP_IPADDR2 << 8) | UIP_IPADDR3)}; |
const u16_t uip_arp_draddr[2] = |
{HTONS((UIP_DRIPADDR0 << 8) | UIP_DRIPADDR1), |
HTONS((UIP_DRIPADDR2 << 8) | UIP_DRIPADDR3)}; |
const u16_t uip_arp_netmask[2] = |
{HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1), |
HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)}; |
#else |
u16_t uip_hostaddr[2]; |
u16_t uip_arp_draddr[2], uip_arp_netmask[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. */ |
volatile u8_t *uip_sappdata; /* The uip_appdata pointer points to the |
application data which is to be sent. */ |
#if UIP_URGDATA > 0 |
volatile u8_t *uip_urgdata; /* The uip_urgdata pointer points to |
urgent data (out-of-band data), if |
present. */ |
u8_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. */ |
|
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 |
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 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 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; |
} |
|
/* 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 != CLOSED && |
conn->lport == htons(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->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; |
conn->lport = htons(lastport); |
conn->rport = 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] = port; |
return; |
} |
} |
} |
/*-----------------------------------------------------------------------------------*/ |
/* XXX: IP fragment reassembly: not well-tested. */ |
|
#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) { |
memcpy(uip_reassbuf, &BUF->vhl, IP_HLEN); |
uip_reasstmr = UIP_REASS_MAXAGE; |
uip_reassflags = 0; |
/* Clear the bitmap. */ |
memset(uip_reassbitmap, sizeof(uip_reassbitmap), 0); |
} |
|
/* 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[IP_HLEN + 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 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; |
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_REASSEMBL */ |
/*-----------------------------------------------------------------------------------*/ |
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; |
|
uip_appdata = &uip_buf[40 + UIP_LLH_LEN]; |
|
|
/* Check if we were invoked because of the perodic timer fireing. */ |
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]; |
} |
} |
} |
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)) { |
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(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]; |
} |
|
/* 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_STAT(++uip_stat.ip.drop); |
UIP_STAT(++uip_stat.ip.fragerr); |
UIP_LOG("ip: fragment dropped."); |
goto drop; |
#endif /* UIP_REASSEMBLY */ |
} |
|
/* 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 0 |
// IP checksum is wrong through Netgear DSL router |
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 |
|
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; |
} |
|
#if UIP_PINGADDRCONF |
icmp_input: |
#endif |
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. */ |
tmp16 = BUF->destipaddr[0]; |
BUF->destipaddr[0] = BUF->srcipaddr[0]; |
BUF->srcipaddr[0] = tmp16; |
tmp16 = BUF->destipaddr[1]; |
BUF->destipaddr[1] = BUF->srcipaddr[1]; |
BUF->srcipaddr[1] = tmp16; |
|
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; |
|
BUF->len[0] = (uip_len >> 8); |
BUF->len[1] = (uip_len & 0xff); |
|
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 1 // FIXME |
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; |
} |
#endif |
|
/* 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; |
|
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 = 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. */ |
tmp16 = BUF->srcport; |
BUF->srcport = BUF->destport; |
BUF->destport = tmp16; |
|
/* Swap IP addresses. */ |
tmp16 = BUF->destipaddr[0]; |
BUF->destipaddr[0] = BUF->srcipaddr[0]; |
BUF->srcipaddr[0] = tmp16; |
tmp16 = BUF->destipaddr[1]; |
BUF->destipaddr[1] = BUF->srcipaddr[1]; |
BUF->srcipaddr[1] = tmp16; |
|
|
/* 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->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_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. */ |
tmp16 = ((u16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | |
(u16_t)uip_buf[40 + 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] = 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_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; |
} |
|
} |
|
/* 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; |
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 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. */ |
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 = 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; |
} |
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); |
} |
|
/* 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 mechanim. |
*/ |
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 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. */ |
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; |
} |
} else { |
uip_connr->len = 0; |
} |
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 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 { |
BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8); |
BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff); |
} |
|
tcp_send_noconn: |
|
BUF->len[0] = (uip_len >> 8); |
BUF->len[1] = (uip_len & 0xff); |
|
/* Calculate TCP checksum. */ |
BUF->tcpchksum = 0; |
BUF->tcpchksum = ~(uip_tcpchksum()); |
|
|
#if UIP_UDP |
ip_send_nolen: |
#endif |
|
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); |
} |
/*-----------------------------------------------------------------------------------*/ |
/** @} */ |