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db8aff6778
nuttx/net/uip/uip.c
patacongo db8aff6778 Verified basic client-side network functionality 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@373 42af7a65-404d-4744-a932-0658087f49c3
2007-11-06 19:58:14 +00:00

2072 lines
59 KiB
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/****************************************************************************
* uip.c
* The uIP TCP/IP stack code.
* author Adam Dunkels <adam@dunkels.com>
*
* uIP is an implementation of the TCP/IP protocol stack intended for
* small 8-bit and 16-bit microcontrollers.
*
* uIP provides the necessary protocols for Internet communication,
* with a very small code footprint and RAM requirements - the uIP
* code size is on the order of a few kilobytes and RAM usage is on
* the order of a few hundred bytes.
*
* Copyright () 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.
*
****************************************************************************/
/****************************************************************************
* 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_interrupt()
* function into many smaller functions, this would increase the code
* size because of the overhead of parameter passing and the fact that
* the optimier would not be as efficient.
*
* The principle is that we have a small buffer, called the d_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 d_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 d_buf. The d_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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_NET
#include <sys/types.h>
#include <sys/ioctl.h>
#include <debug.h>
#include <string.h>
#include <net/uip/uipopt.h>
#include <net/uip/uip.h>
#include <net/uip/uip-arch.h>
#ifdef CONFIG_NET_IPv6
# include "uip-neighbor.h"
#endif /* CONFIG_NET_IPv6 */
/* Check if logging of network events should be compiled in.
*
* This is useful mostly for debugging. The function uip_log()
* must be implemented to suit the architecture of the project, if
* logging is turned on.
*/
#ifdef CONFIG_NET_LOGGING
# include <stdio.h>
extern void uip_log(char *msg);
# define UIP_LOG(m) uip_log(m)
#else
# define UIP_LOG(m)
#endif
#include "uip-internal.h"
/****************************************************************************
* 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 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 *)&dev->d_buf[UIP_LLH_LEN])
#define FBUF ((struct uip_tcpip_hdr *)&uip_reassbuf[0])
#define ICMPBUF ((struct uip_icmpip_hdr *)&dev->d_buf[UIP_LLH_LEN])
#define UDPBUF ((struct uip_udpip_hdr *)&dev->d_buf[UIP_LLH_LEN])
/****************************************************************************
* Public Variables
****************************************************************************/
#if UIP_URGDATA > 0
void *uip_urgdata; /* urgent data (out-of-band data), if present. */
uint16 uip_urglen; /* Length of (received) urgent data */
#endif
/* The uip_flags variable is used for communication between the TCP/IP
* stack and the application program.
*/
uint8 uip_flags;
/* uip_conn always points to the current connection. */
struct uip_conn *uip_conn;
#ifdef CONFIG_NET_UDP
struct uip_udp_conn *uip_udp_conn;
#endif /* CONFIG_NET_UDP */
/* Temporary variables. */
uint8 uip_acc32[4];
#if UIP_STATISTICS == 1
struct uip_stats uip_stat;
# define UIP_STAT(s) s
#else
# define UIP_STAT(s)
#endif /* UIP_STATISTICS == 1 */
const uip_ipaddr_t all_ones_addr =
#ifdef CONFIG_NET_IPv6
{0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff,0xffff};
#else /* CONFIG_NET_IPv6 */
{0xffffffff};
#endif /* CONFIG_NET_IPv6 */
const uip_ipaddr_t all_zeroes_addr =
#ifdef CONFIG_NET_IPv6
{0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000};
#else /* CONFIG_NET_IPv6 */
{0x00000000};
#endif /* CONFIG_NET_IPv6 */
/****************************************************************************
* Private Variables
****************************************************************************/
static uint16 g_ipid; /* Increasing number used for the IP ID field. */
/****************************************************************************
* Private Functions
****************************************************************************/
#if !UIP_ARCH_CHKSUM
static uint16 chksum(uint16 sum, const uint8 *data, uint16 len)
{
uint16 t;
const uint8 *dataptr;
const uint8 *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;
}
static uint16 upper_layer_chksum(struct uip_driver_s *dev, uint8 proto)
{
uint16 upper_layer_len;
uint16 sum;
#ifdef CONFIG_NET_IPv6
upper_layer_len = (((uint16)(BUF->len[0]) << 8) + BUF->len[1]);
#else /* CONFIG_NET_IPv6 */
upper_layer_len = (((uint16)(BUF->len[0]) << 8) + BUF->len[1]) - UIP_IPH_LEN;
#endif /* CONFIG_NET_IPv6 */
/* First sum pseudoheader. */
/* IP protocol and length fields. This addition cannot carry. */
sum = upper_layer_len + proto;
/* Sum IP source and destination addresses. */
sum = chksum(sum, (uint8 *)&BUF->srcipaddr, 2 * sizeof(uip_ipaddr_t));
/* Sum TCP header and data. */
sum = chksum(sum, &dev->d_buf[UIP_IPH_LEN + UIP_LLH_LEN], upper_layer_len);
return (sum == 0) ? 0xffff : htons(sum);
}
#ifdef CONFIG_NET_IPv6
static uint16 uip_icmp6chksum(struct uip_driver_s *dev)
{
return upper_layer_chksum(dev, UIP_PROTO_ICMP6);
}
#endif /* CONFIG_NET_IPv6 */
#endif /* UIP_ARCH_CHKSUM */
/****************************************************************************
* Public Functions
****************************************************************************/
/* This function may be used at boot time to set the initial ip_id.*/
void uip_setipid(uint16 id)
{
g_ipid = id;
}
/* Calculate the Internet checksum over a buffer. */
#if !UIP_ARCH_ADD32
void uip_add32(uint8 *op32, uint16 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
uint16 uip_chksum(uint16 *data, uint16 len)
{
return htons(chksum(0, (uint8 *)data, len));
}
/* Calculate the IP header checksum of the packet header in d_buf. */
#ifndef UIP_ARCH_IPCHKSUM
uint16 uip_ipchksum(struct uip_driver_s *dev)
{
uint16 sum;
sum = chksum(0, &dev->d_buf[UIP_LLH_LEN], UIP_IPH_LEN);
return (sum == 0) ? 0xffff : htons(sum);
}
#endif
/* Calculate the TCP checksum of the packet in d_buf and d_appdata. */
uint16 uip_tcpchksum(struct uip_driver_s *dev)
{
return upper_layer_chksum(dev, UIP_PROTO_TCP);
}
/* Calculate the UDP checksum of the packet in d_buf and d_appdata. */
#ifdef CONFIG_NET_UDP_CHECKSUMS
uint16 uip_udpchksum(struct uip_driver_s *dev)
{
return upper_layer_chksum(dev, UIP_PROTO_UDP);
}
#endif /* UIP_UDP_CHECKSUMS */
#endif /* UIP_ARCH_CHKSUM */
void uip_init(void)
{
/* Initialize the listening port structures */
uip_listeninit();
/* Initialize the TCP/IP connection structures */
uip_tcpinit();
/* Initialize the UDP connection structures */
#ifdef CONFIG_NET_UDP
uip_udpinit();
#endif
/* IPv4 initialization. */
}
/* IP fragment reassembly: not well-tested. */
#if UIP_REASSEMBLY && !defined(CONFIG_NET_IPv6)
#define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
static uint8 uip_reassbuf[UIP_REASS_BUFSIZE];
static uint8 uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
static const uint8 bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f, 0x0f, 0x07, 0x03, 0x01};
static uint16 uip_reasslen;
static uint8 uip_reassflags;
#define UIP_REASS_FLAG_LASTFRAG 0x01
static uint8 uip_reasstmr;
#define IP_MF 0x20
static uint8 uip_reass(void)
{
uint16 offset, len;
uint16 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 (uiphdr_addr_cmp(BUF->srcipaddr, FBUF->srcipaddr) &&
uiphdr_addr_cmp(BUF->destipaddr == FBUF->destipaddr) &&
BUF->g_ipid[0] == FBUF->g_ipid[0] && BUF->g_ipid[1] == FBUF->g_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 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)] != (uint8)~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(dev));
return uip_reasslen;
}
}
nullreturn:
return 0;
}
#endif /* UIP_REASSEMBLY */
static void uip_add_rcv_nxt(uint16 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];
}
#ifdef CONFIG_NET_UDP
static void uip_udp_callback(struct uip_driver_s *dev)
{
vdbg("uip_flags: %02x\n", uip_flags);
/* Some sanity checking */
if (uip_udp_conn && uip_udp_conn->event)
{
/* Perform the callback */
uip_udp_conn->event(dev, uip_udp_conn->private);
}
}
#endif
static void uip_tcp_callback(struct uip_driver_s *dev)
{
vdbg("uip_flags: %02x\n", uip_flags);
/* Some sanity checking */
if (uip_conn)
{
/* Check if there is a data callback */
if (uip_conn->data_event)
{
/* Perform the callback */
uip_conn->data_event(dev, uip_conn->data_private);
}
/* Check if there is a connection-related event and a connection
* callback.
*/
if (((uip_flags & UIP_CONN_EVENTS) != 0) && uip_conn->connection_event)
{
/* Perform the callback */
uip_conn->connection_event(uip_conn->connection_private);
}
}
}
void uip_interrupt(struct uip_driver_s *dev, uint8 event)
{
register struct uip_conn *uip_connr = uip_conn;
uint16 tmp16;
uint8 seqbyte;
uint8 opt;
int len;
int i;
vdbg("event: %d\n", event);
dev->d_snddata = dev->d_appdata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
/* Check if we were invoked because of a TX poll request for a
* particular TCP connection.
*/
if (event == UIP_DRV_POLL)
{
if ((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED &&
!uip_outstanding(uip_connr))
{
uip_flags = UIP_POLL;
uip_tcp_callback(dev);
goto appsend;
}
goto drop;
}
/* Check if we were invoked because of the perodic timer firing. */
else if (event == UIP_DRV_TIMER)
{
#if UIP_REASSEMBLY
if (uip_reasstmr != 0)
{
--uip_reasstmr;
}
#endif /* UIP_REASSEMBLY */
/* Increase the TCP sequence number */
uip_tcpnextsequence();
/* Reset the length variables. */
dev->d_len = 0;
dev->d_sndlen = 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;
vdbg("TCP state: UIP_CLOSED\n");
}
}
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;
vdbg("TCP state: UIP_CLOSED\n");
/* We call uip_tcp_callback() with uip_flags set to
* UIP_TIMEDOUT to inform the application that the
* connection has timed out.
*/
uip_flags = UIP_TIMEDOUT;
uip_tcp_callback(dev);
/* 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 & UIP_TS_MASK)
{
case UIP_SYN_RCVD:
/* In the SYN_RCVD state, we should retransmit our
* SYNACK.
*/
goto tcp_send_synack;
case UIP_SYN_SENT:
/* In the SYN_SENT state, we retransmit out SYN. */
BUF->flags = 0;
goto tcp_send_syn;
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_tcp_callback(dev);
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_flags = UIP_POLL;
uip_tcp_callback(dev);
goto appsend;
}
}
goto drop;
}
#ifdef CONFIG_NET_UDP
else if (event == UIP_DRV_UDPPOLL)
{
if (uip_udp_conn->lport != 0)
{
uip_conn = NULL;
dev->d_snddata = dev->d_appdata = &dev->d_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
dev->d_len = 0;
dev->d_sndlen = 0;
uip_flags = UIP_POLL;
uip_udp_callback(dev);
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. */
#ifdef CONFIG_NET_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 /* CONFIG_NET_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 /* CONFIG_NET_IPv6 */
/* Check the size of the packet. If the size reported to us in d_len is
* smaller the size reported in the IP header, we assume that the packet
* has been corrupted in transit. If the size of d_len is larger than the
* size reported in the IP packet header, the packet has been padded and
* we set d_len to the correct value.
*/
if ((BUF->len[0] << 8) + BUF->len[1] <= dev->d_len)
{
dev->d_len = (BUF->len[0] << 8) + BUF->len[1];
#ifdef CONFIG_NET_IPv6
/* The length reported in the IPv6 header is the length of the
* payload that follows the header. However, uIP uses the d_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).
*/
dev->d_len += 40;
#endif /* CONFIG_NET_IPv6 */
}
else
{
UIP_LOG("ip: packet shorter than reported in IP header.");
goto drop;
}
#ifndef CONFIG_NET_IPv6
/* Check the fragment flag. */
if ((BUF->ipoffset[0] & 0x3f) != 0 || BUF->ipoffset[1] != 0)
{
#if UIP_REASSEMBLY
dev->d_len = uip_reass();
if (dev->d_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 /* CONFIG_NET_IPv6 */
if (uip_ipaddr_cmp(dev->d_ipaddr, 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 && !CONFIG_NET_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
if (BUF->proto == UIP_PROTO_UDP && uip_ipaddr_cmp(BUF->destipaddr, all_ones_addr)
{
goto udp_input;
}
#endif /* UIP_BROADCAST */
/* Check if the packet is destined for our IP address. */
#ifndef CONFIG_NET_IPv6
if (!uip_ipaddr_cmp(uip_ip4addr_conv(BUF->destipaddr), dev->d_ipaddr))
{
UIP_STAT(++uip_stat.ip.drop);
goto drop;
}
#else /* CONFIG_NET_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, dev->d_ipaddr) &&
BUF->destipaddr & HTONL(0xffff0000) != HTONL(0xff020000))
{
UIP_STAT(++uip_stat.ip.drop);
goto drop;
}
#endif /* CONFIG_NET_IPv6 */
}
#ifndef CONFIG_NET_IPv6
if (uip_ipchksum(dev) != 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 /* CONFIG_NET_IPv6 */
if (BUF->proto == UIP_PROTO_TCP)
{
/* Check for TCP packet. If so, proceed with TCP input processing. */
goto tcp_input;
}
#ifdef CONFIG_NET_UDP
if (BUF->proto == UIP_PROTO_UDP)
{
goto udp_input;
}
#endif /* CONFIG_NET_UDP */
#ifndef CONFIG_NET_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_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 (dev->d_ipaddr == 0)
{
dev->d_ipaddr = 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. */
uiphdr_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
uiphdr_ipaddr_copy(BUF->srcipaddr, &dev->d_ipaddr);
UIP_STAT(++uip_stat.icmp.sent);
goto send;
#else /* !CONFIG_NET_IPv6 */
/* This is IPv6 ICMPv6 processing code. */
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, dev->d_ipaddr))
{
if (ICMPBUF->options[0] == ICMP6_OPTION_SOURCE_LINK_ADDRESS)
{
/* Save the sender's address in our neighbor list. */
uiphdr_neighbor_add(ICMPBUF->srcipaddr, &(ICMPBUF->options[2]));
}
/* We should now send a neighbor advertisement back to where the
* neighbor solicication came from.
*/
ICMPBUF->type = ICMP6_NEIGHBOR_ADVERTISEMENT;
ICMPBUF->flags = ICMP6_FLAG_S; /* Solicited flag. */
ICMPBUF->reserved1 = ICMPBUF->reserved2 = ICMPBUF->reserved3 = 0;
uiphdr_ipaddr_copy(ICMPBUF->destipaddr, ICMPBUF->srcipaddr);
uiphdr_ipaddr_copy(ICMPBUF->srcipaddr, dev->d_ipaddr);
ICMPBUF->options[0] = ICMP6_OPTION_TARGET_LINK_ADDRESS;
ICMPBUF->options[1] = 1; /* Options length, 1 = 8 bytes. */
memcpy(&(ICMPBUF->options[2]), &dev->d_mac, IFHWADDRLEN);
ICMPBUF->icmpchksum = 0;
ICMPBUF->icmpchksum = ~uip_icmp6chksum(dev);
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;
uiphdr_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
uiphdr_ipaddr_copy(BUF->srcipaddr, dev->d_ipaddr);
ICMPBUF->icmpchksum = 0;
ICMPBUF->icmpchksum = ~uip_icmp6chksum(dev);
UIP_STAT(++uip_stat.icmp.sent);
goto send;
}
else
{
UIP_STAT(++uip_stat.icmp.drop);
UIP_STAT(++uip_stat.icmp.typeerr);
UIP_LOG("icmp: unknown ICMP message.");
goto drop;
}
#endif /* !CONFIG_NET_IPv6 */
#ifdef CONFIG_NET_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 d_sndlen, it has a packet to
* send.
*/
#ifdef CONFIG_NET_UDP_CHECKSUMS
dev->d_len -= UIP_IPUDPH_LEN;
dev->d_appdata = &dev->d_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
if (UDPBUF->udpchksum != 0 && uip_udpchksum(dev) != 0xffff)
{
UIP_STAT(++uip_stat.udp.drop);
UIP_STAT(++uip_stat.udp.chkerr);
UIP_LOG("udp: bad checksum.");
goto drop;
}
#else /* UIP_UDP_CHECKSUMS */
dev->d_len -= UIP_IPUDPH_LEN;
#endif /* UIP_UDP_CHECKSUMS */
/* Demultiplex this UDP packet between the UDP "connections". */
uip_udp_conn = uip_udpactive(UDPBUF);
if (uip_udp_conn)
{
goto udp_found;
}
UIP_LOG("udp: no matching connection found");
goto drop;
udp_found:
uip_conn = NULL;
uip_flags = UIP_NEWDATA;
dev->d_snddata = dev->d_appdata = &dev->d_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
dev->d_sndlen = 0;
uip_udp_callback(dev);
udp_send:
if (dev->d_sndlen == 0)
{
goto drop;
}
dev->d_len = dev->d_sndlen + UIP_IPUDPH_LEN;
#ifdef CONFIG_NET_IPv6
/* For IPv6, the IP length field does not include the IPv6 IP header
* length.
*/
BUF->len[0] = ((dev->d_len - UIP_IPH_LEN) >> 8);
BUF->len[1] = ((dev->d_len - UIP_IPH_LEN) & 0xff);
#else /* CONFIG_NET_IPv6 */
BUF->len[0] = (dev->d_len >> 8);
BUF->len[1] = (dev->d_len & 0xff);
#endif /* CONFIG_NET_IPv6 */
BUF->ttl = uip_udp_conn->ttl;
BUF->proto = UIP_PROTO_UDP;
UDPBUF->udplen = HTONS(dev->d_sndlen + UIP_UDPH_LEN);
UDPBUF->udpchksum = 0;
BUF->srcport = uip_udp_conn->lport;
BUF->destport = uip_udp_conn->rport;
uiphdr_ipaddr_copy(BUF->srcipaddr, &dev->d_ipaddr);
uiphdr_ipaddr_copy(BUF->destipaddr, &uip_udp_conn->ripaddr);
dev->d_appdata = &dev->d_buf[UIP_LLH_LEN + UIP_IPTCPH_LEN];
#ifdef CONFIG_NET_UDP_CHECKSUMS
/* Calculate UDP checksum. */
UDPBUF->udpchksum = ~(uip_udpchksum(dev));
if (UDPBUF->udpchksum == 0)
{
UDPBUF->udpchksum = 0xffff;
}
#endif /* UIP_UDP_CHECKSUMS */
goto ip_send_nolen;
#endif /* CONFIG_NET_UDP */
/* TCP input processing. */
tcp_input:
UIP_STAT(++uip_stat.tcp.recv);
/* Start of TCP input header processing code. */
if (uip_tcpchksum(dev) != 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. */
uip_connr = uip_tcpactive(BUF);
if (uip_connr)
{
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. */
if (uip_islistener(tmp16))
{
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;
dev->d_len = UIP_IPTCPH_LEN;
BUF->tcpoffset = 5 << 4;
/* Flip the seqno and ackno fields in the TCP header. */
seqbyte = BUF->seqno[3];
BUF->seqno[3] = BUF->ackno[3];
BUF->ackno[3] = seqbyte;
seqbyte = BUF->seqno[2];
BUF->seqno[2] = BUF->ackno[2];
BUF->ackno[2] = seqbyte;
seqbyte = BUF->seqno[1];
BUF->seqno[1] = BUF->ackno[1];
BUF->ackno[1] = seqbyte;
seqbyte = BUF->seqno[0];
BUF->seqno[0] = BUF->ackno[0];
BUF->ackno[0] = seqbyte;
/* 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. */
uiphdr_ipaddr_copy(BUF->destipaddr, BUF->srcipaddr);
uiphdr_ipaddr_copy(BUF->srcipaddr, dev->d_ipaddr);
/* 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 allocate a new connection structure and see if there is any
* user application to accept it.
*/
uip_connr = uip_tcpaccept(BUF);
if (uip_connr)
{
/* The connection structure was successfully allocated. Now see
* there is an application waiting to accept the connection (or at
* least queue it it for acceptance).
*/
if (uip_accept(uip_connr, tmp16) != OK)
{
/* No, then we have to give the connection back */
uip_tcpfree(uip_connr);
uip_connr = NULL;
}
}
if (!uip_connr)
{
/* Either (1) all available connections are in use, or (2) there is no
* application in place to accept the connection. We drop packet and hope that
* the remote end will retransmit the packet at a time when we
* have more spare connections or someone waiting to accept the connection.
*/
UIP_STAT(++uip_stat.tcp.syndrop);
UIP_LOG("tcp: found no unused connections.");
goto drop;
}
uip_add_rcv_nxt(1);
uip_conn = uip_connr;
/* Parse the TCP MSS option, if present. */
if ((BUF->tcpoffset & 0xf0) > 0x50)
{
for (i = 0; i < ((BUF->tcpoffset >> 4) - 5) << 2 ;)
{
opt = dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + i];
if (opt == TCP_OPT_END)
{
/* End of options. */
break;
}
else if (opt == TCP_OPT_NOOP)
{
/* NOP option. */
++i;
}
else if (opt == TCP_OPT_MSS &&
dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == TCP_OPT_MSS_LEN)
{
/* An MSS option with the right option length. */
tmp16 = ((uint16)dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) |
(uint16)dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + i];
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 (dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == 0)
{
/* If the length field is zero, the options are malformed
* and we don't process them further.
*/
break;
}
i += dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i];
}
}
}
/* Our response will be a SYNACK. */
tcp_send_synack:
BUF->flags = TCP_ACK;
tcp_send_syn:
BUF->flags |= TCP_SYN;
/* 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;
dev->d_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 wihtin our advertised window
* before we accept the reset.
*/
if (BUF->flags & TCP_RST)
{
uip_connr->tcpstateflags = UIP_CLOSED;
vdbg("TCP state: UIP_CLOSED\n");
UIP_LOG("tcp: got reset, aborting connection.");
uip_flags = UIP_ABORT;
uip_tcp_callback(dev);
goto drop;
}
/* Calculated the length of the data, if the application has sent
* any data to us.
*/
len = (BUF->tcpoffset >> 4) << 2;
/* d_len will contain the length of the actual TCP data. This is
* calculated by subtracing the length of the TCP header (in
* len) and the length of the IP header (20 bytes).
*/
dev->d_len -= (len + 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 ((dev->d_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_connr->len = 0;
vdbg("TCP state: UIP_ESTABLISHED\n");
uip_flags = UIP_CONNECTED;
if (dev->d_len > 0)
{
uip_flags |= UIP_NEWDATA;
uip_add_rcv_nxt(dev->d_len);
}
dev->d_sndlen = 0;
uip_tcp_callback(dev);
goto appsend;
}
goto drop;
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 (i = 0; i < ((BUF->tcpoffset >> 4) - 5) << 2 ;)
{
opt = dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + i];
if (opt == TCP_OPT_END)
{
/* End of options. */
break;
}
else if (opt == TCP_OPT_NOOP)
{
/* NOP option. */
++i;
}
else if (opt == TCP_OPT_MSS &&
dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == TCP_OPT_MSS_LEN)
{
/* An MSS option with the right option length. */
tmp16 =
(dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) |
dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + i];
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 (dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i] == 0)
{
/* If the length field is zero, the options are
* malformed and we don't process them further.
*/
break;
}
i += dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + i];
}
}
}
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];
vdbg("TCP state: UIP_ESTABLISHED\n");
uip_add_rcv_nxt(1);
uip_flags = UIP_CONNECTED | UIP_NEWDATA;
uip_connr->len = 0;
dev->d_len = 0;
dev->d_sndlen = 0;
uip_tcp_callback(dev);
goto appsend;
}
/* Inform the application that the connection failed */
uip_flags = UIP_ABORT;
uip_tcp_callback(dev);
/* The connection is closed after we send the RST */
uip_conn->tcpstateflags = UIP_CLOSED;
vdbg("TCP state: UIP_CLOSED\n");
goto reset;
case UIP_ESTABLISHED:
/* In the ESTABLISHED state, we call upon the application to feed
* data into the d_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(dev->d_len + 1);
uip_flags |= UIP_CLOSE;
if (dev->d_len > 0)
{
uip_flags |= UIP_NEWDATA;
}
uip_tcp_callback(dev);
uip_connr->tcpstateflags = UIP_LAST_ACK;
uip_connr->len = 1;
uip_connr->nrtx = 0;
vdbg("TCP state: UIP_LAST_ACK\n");
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 > dev->d_len)
{
/* There is more urgent data in the next segment to come. */
uip_urglen = dev->d_len;
}
uip_add_rcv_nxt(uip_urglen);
dev->d_len -= uip_urglen;
uip_urgdata = dev->d_appdata;
dev->d_appdata += uip_urglen;
}
else
{
uip_urglen = 0;
#else /* UIP_URGDATA > 0 */
dev->d_appdata =
((uint8*)dev->d_appdata) + ((BUF->urgp[0] << 8) | BUF->urgp[1]);
dev->d_len -=
(BUF->urgp[0] << 8) | BUF->urgp[1];
#endif /* UIP_URGDATA > 0 */
}
/* If d_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 (dev->d_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED))
{
uip_flags |= UIP_NEWDATA;
uip_add_rcv_nxt(dev->d_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 = ((uint16)BUF->wnd[0] << 8) + (uint16)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 d_len field
* contains the length of the incoming data. The application can
* access the incoming data through the global pointer
* d_appdata, which usually points UIP_IPTCPH_LEN + UIP_LLH_LEN
* bytes into the d_buf array.
*
* If the application wishes to send any data, this data should be
* put into the d_appdata and the length of the data should be
* put into d_len. If the application don't have any data to
* send, d_len must be set to 0.
*/
if (uip_flags & (UIP_NEWDATA | UIP_ACKDATA))
{
dev->d_sndlen = 0;
uip_tcp_callback(dev);
appsend:
if (uip_flags & UIP_ABORT)
{
dev->d_sndlen = 0;
uip_connr->tcpstateflags = UIP_CLOSED;
vdbg("TCP state: UIP_CLOSED\n");
BUF->flags = TCP_RST | TCP_ACK;
goto tcp_send_nodata;
}
if (uip_flags & UIP_CLOSE)
{
uip_connr->tcpstateflags = UIP_FIN_WAIT_1;
uip_connr->len = 1;
uip_connr->nrtx = 0;
vdbg("TCP state: UIP_FIN_WAIT_1\n");
BUF->flags = TCP_FIN | TCP_ACK;
dev->d_sndlen = 0;
goto tcp_send_nodata;
}
/* If d_sndlen > 0, the application has data to be sent. */
if (dev->d_sndlen > 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 (dev->d_sndlen > uip_connr->mss)
{
dev->d_sndlen = uip_connr->mss;
}
/* Remember how much data we send out now so that we
* know when everything has been acknowledged.
*/
uip_connr->len = dev->d_sndlen;
}
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.
*/
dev->d_sndlen = uip_connr->len;
}
}
uip_connr->nrtx = 0;
apprexmit:
dev->d_appdata = dev->d_snddata;
/* 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 (dev->d_sndlen > 0 && uip_connr->len > 0)
{
/* Add the length of the IP and TCP headers. */
dev->d_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)
{
dev->d_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;
vdbg("TCP state: UIP_CLOSED\n");
uip_flags = UIP_CLOSE;
uip_tcp_callback(dev);
}
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 (dev->d_len > 0)
{
uip_add_rcv_nxt(dev->d_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;
vdbg("TCP state: UIP_TIME_WAIT\n");
}
else
{
uip_connr->tcpstateflags = UIP_CLOSING;
vdbg("TCP state: UIP_CLOSING\n");
}
uip_add_rcv_nxt(1);
uip_flags = UIP_CLOSE;
uip_tcp_callback(dev);
goto tcp_send_ack;
}
else if (uip_flags & UIP_ACKDATA)
{
uip_connr->tcpstateflags = UIP_FIN_WAIT_2;
uip_connr->len = 0;
vdbg("TCP state: UIP_FIN_WAIT_2\n");
goto drop;
}
if (dev->d_len > 0)
{
goto tcp_send_ack;
}
goto drop;
case UIP_FIN_WAIT_2:
if (dev->d_len > 0)
{
uip_add_rcv_nxt(dev->d_len);
}
if (BUF->flags & TCP_FIN)
{
uip_connr->tcpstateflags = UIP_TIME_WAIT;
uip_connr->timer = 0;
vdbg("TCP state: UIP_TIME_WAIT\n");
uip_add_rcv_nxt(1);
uip_flags = UIP_CLOSE;
uip_tcp_callback(dev);
goto tcp_send_ack;
}
if (dev->d_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;
vdbg("TCP state: UIP_TIME_WAIT\n");
}
}
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:
dev->d_len = UIP_IPTCPH_LEN;
tcp_send_noopts:
BUF->tcpoffset = (UIP_TCPH_LEN / 4) << 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;
uiphdr_ipaddr_copy(BUF->srcipaddr, &dev->d_ipaddr);
uiphdr_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;
#ifdef CONFIG_NET_IPv6
/* For IPv6, the IP length field does not include the IPv6 IP header
* length.
*/
BUF->len[0] = ((dev->d_len - UIP_IPH_LEN) >> 8);
BUF->len[1] = ((dev->d_len - UIP_IPH_LEN) & 0xff);
#else /* CONFIG_NET_IPv6 */
BUF->len[0] = (dev->d_len >> 8);
BUF->len[1] = (dev->d_len & 0xff);
#endif /* CONFIG_NET_IPv6 */
BUF->urgp[0] = BUF->urgp[1] = 0;
/* Calculate TCP checksum. */
BUF->tcpchksum = 0;
BUF->tcpchksum = ~(uip_tcpchksum(dev));
#ifdef CONFIG_NET_UDP
ip_send_nolen:
#endif /* CONFIG_NET_UDP */
#ifdef CONFIG_NET_IPv6
BUF->vtc = 0x60;
BUF->tcflow = 0x00;
BUF->flow = 0x00;
#else /* CONFIG_NET_IPv6 */
BUF->vhl = 0x45;
BUF->tos = 0;
BUF->ipoffset[0] = 0;
BUF->ipoffset[1] = 0;
++g_ipid;
BUF->ipid[0] = g_ipid >> 8;
BUF->ipid[1] = g_ipid & 0xff;
/* Calculate IP checksum. */
BUF->ipchksum = 0;
BUF->ipchksum = ~(uip_ipchksum(dev));
#endif /* CONFIG_NET_IPv6 */
UIP_STAT(++uip_stat.tcp.sent);
send:
vdbg("Sending packet length %d (%d)\n",
dev->d_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:
dev->d_len = 0;
uip_flags = 0;
return;
}
#endif /* CONFIG_NET */
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