uhd

/*

 * Copyright 2009-2012 Ettus Research LLC

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include "net_common.h"

#include "banal.h"

#include <hal_io.h>

#include <memory_map.h>

#include <memcpy_wa.h>

#include <ethernet.h>

#include <net/padded_eth_hdr.h>

#include <lwip/ip.h>

#include <lwip/udp.h>

#include <lwip/icmp.h>

#include <stdlib.h>

#include <nonstdio.h>

#include "arp_cache.h"

#include "if_arp.h"

#include <ethertype.h>

#include <string.h>

#include "pkt_ctrl.h"

/***********************************************************************

 * Constants + Globals

 **********************************************************************/

static const bool debug = false;

static const size_t out_buff_size = 2048;

static const eth_mac_addr_t BCAST_MAC_ADDR = {{0xff, 0xff, 0xff, 0xff, 0xff, 0xff}};

#define MAX_UDP_LISTENERS 10

/***********************************************************************

 * 16-bit one's complement sum

 **********************************************************************/

static uint32_t chksum_buffer(

    uint16_t *buf, size_t nshorts,

    uint32_t initial_chksum

){

    uint32_t chksum = initial_chksum;

    for (size_t i = 0; i < nshorts; i++) chksum += buf[i];

    while (chksum >> 16) chksum = (chksum & 0xffff) + (chksum >> 16);

    return chksum;

}

/***********************************************************************

 * Listener registry

 **********************************************************************/

static eth_mac_addr_t _local_mac_addr;

static struct ip_addr _local_ip_addr;

void register_addrs(const eth_mac_addr_t *mac_addr, const struct ip_addr *ip_addr){

    _local_mac_addr = *mac_addr;

    _local_ip_addr = *ip_addr;

}

struct listener_entry {

  unsigned short        port;

  udp_receiver_t        rcvr;

};

static struct listener_entry listeners[MAX_UDP_LISTENERS];

void init_udp_listeners(void){

    for (int i = 0; i < MAX_UDP_LISTENERS; i++){

        listeners[i].rcvr = NULL;

    }

}

static struct listener_entry *

find_listener_by_port(unsigned short port)

{

  for (int i = 0; i < MAX_UDP_LISTENERS; i++){

    if (port == listeners[i].port)

      return &listeners[i];

  }

  return 0;

}

static struct listener_entry *

find_free_listener(void)

{

  for (int i = 0; i < MAX_UDP_LISTENERS; i++){

    if (listeners[i].rcvr == NULL)

      return &listeners[i];

  }

  abort();

}

void

register_udp_listener(int port, udp_receiver_t rcvr)

{

  struct listener_entry *lx = find_listener_by_port(port);

  if (lx)

    lx->rcvr = rcvr;

  else {

    lx = find_free_listener();

    lx->port = port;

    lx->rcvr = rcvr;

  }

}

/***********************************************************************

 * Protocol framer

 **********************************************************************/

void setup_framer(

    eth_mac_addr_t eth_dst,

    eth_mac_addr_t eth_src,

    struct socket_address sock_dst,

    struct socket_address sock_src,

    size_t which

){

    struct {

        padded_eth_hdr_t eth;

        struct ip_hdr ip;

        struct udp_hdr udp;

    } frame;

    //-- load Ethernet header --//

    frame.eth.dst = eth_dst;

    frame.eth.src = eth_src;

    frame.eth.ethertype = ETHERTYPE_IPV4;

    //-- load IPv4 header --//

    IPH_VHLTOS_SET(&frame.ip, 4, 5, 0);

    IPH_LEN_SET(&frame.ip, 0);

    IPH_ID_SET(&frame.ip, 0);

    IPH_OFFSET_SET(&frame.ip, IP_DF); // don't fragment

    IPH_TTL_SET(&frame.ip, 32);

    IPH_PROTO_SET(&frame.ip, IP_PROTO_UDP);

    IPH_CHKSUM_SET(&frame.ip, 0);

    frame.ip.src = sock_src.addr;

    frame.ip.dest = sock_dst.addr;

    IPH_CHKSUM_SET(&frame.ip, chksum_buffer(

        (unsigned short *) &frame.ip,

        sizeof(frame.ip)/sizeof(short), 0

    ));

    //-- load UDP header --//

    frame.udp.src = sock_src.port;

    frame.udp.dest = sock_dst.port;

    frame.udp.len = 0;

    frame.udp.chksum = 0;

    //copy into the framer table registers

    memcpy_wa((void *)(sr_proto_framer_regs->table[which].entry + 1), &frame, sizeof(frame));

}

/***********************************************************************

 * Slow-path packet framing and transmission

 **********************************************************************/

/*!

 * low level routine to assembly an ethernet frame and send it.

 *

 * \param dst destination mac address

 * \param ethertype ethertype field

 * \param buf0 first part of data

 * \param len0 length of first part of data

 * \param buf1 second part of data

 * \param len1 length of second part of data

 * \param buf2 third part of data

 * \param len2 length of third part of data

 */

static void

send_pkt(

    eth_mac_addr_t dst, int ethertype,

    const void *buf0, size_t len0,

    const void *buf1, size_t len1,

    const void *buf2, size_t len2

){

    //control word for framed data

    uint32_t ctrl_word = 0x0;

    //assemble the ethernet header

    padded_eth_hdr_t ehdr;

    ehdr.pad = 0;

    ehdr.dst = dst;

    ehdr.src = _local_mac_addr;

    ehdr.ethertype = ethertype;

    //grab an out buffer and pointer

    uint8_t *buff = (uint8_t *)pkt_ctrl_claim_outgoing_buffer();

    uint8_t *p = buff;

    size_t total_len = 0;

    //create a list of all buffers to copy

    const void *buffs[] = {&ctrl_word, &ehdr, buf0, buf1, buf2};

    size_t lens[] = {sizeof(ctrl_word), sizeof(ehdr), len0, len1, (len2 + 3) & ~3};

    //copy each buffer into the out buffer

    for (size_t i = 0; i < sizeof(buffs)/sizeof(buffs[0]); i++){

        total_len += lens[i]; //use full length (not clipped)

        size_t bytes_remaining = out_buff_size - (size_t)(p - buff);

        if (lens[i] > bytes_remaining) lens[i] = bytes_remaining;

        if (lens[i] && ((lens[i] & 0x3) || (intptr_t) buffs[i] & 0x3))

            printf("send_pkt: bad alignment of len and/or buf\n");

        memcpy_wa(p, buffs[i], lens[i]);

        p += lens[i];

    }

    //ensure that minimum length requirements are met

    if (total_len < 64) total_len = 64; //60 + ctrl word

    pkt_ctrl_commit_outgoing_buffer(total_len/sizeof(uint32_t));

    if (debug) printf("sent %d bytes\n", (int)total_len);

}

void

send_ip_pkt(struct ip_addr dst, int protocol,

            const void *buf0, size_t len0,

            const void *buf1, size_t len1)

{

  struct ip_hdr ip;

  IPH_VHLTOS_SET(&ip, 4, 5, 0);

  IPH_LEN_SET(&ip, IP_HLEN + len0 + len1);

  IPH_ID_SET(&ip, 0);

  IPH_OFFSET_SET(&ip, IP_DF);        /* don't fragment */

  IPH_TTL_SET(&ip, 32);

  IPH_PROTO_SET(&ip, protocol);

  IPH_CHKSUM_SET(&ip, 0);

  ip.src = _local_ip_addr;

  ip.dest = dst;

  IPH_CHKSUM_SET(&ip, ~chksum_buffer(

    (unsigned short *) &ip, sizeof(ip)/sizeof(short), 0

  ));

  eth_mac_addr_t dst_mac;

  bool found = arp_cache_lookup_mac(&ip.dest, &dst_mac);

  if (!found){

    printf("net_common: failed to hit cache looking for ");

    print_ip_addr(&ip.dest);

    newline();

    return;

  }

  send_pkt(dst_mac, ETHERTYPE_IPV4,

           &ip, sizeof(ip), buf0, len0, buf1, len1);

}

void 

send_udp_pkt(int src_port, struct socket_address dst,

             const void *buf, size_t len)

{

  struct udp_hdr udp _AL4;

  udp.src = src_port;

  udp.dest = dst.port;

  udp.len = UDP_HLEN + len;

  udp.chksum = 0;

  send_ip_pkt(dst.addr, IP_PROTO_UDP,

              &udp, sizeof(udp), buf, len);

}

static void

handle_udp_packet(struct ip_addr src_ip, struct ip_addr dst_ip,

                  struct udp_hdr *udp, size_t len)

{

  if (len != udp->len){

    printf("UDP inconsistent lengths: %d %d\n", (int)len, udp->len);

    return;

  }

  unsigned char *payload = ((unsigned char *) udp) + UDP_HLEN;

  int payload_len = len - UDP_HLEN;

  if (0){

    printf("\nUDP: src = %d  dst = %d  len = %d\n",

           udp->src, udp->dest, udp->len);

    //print_bytes(0, payload, payload_len);

  }

  struct listener_entry *lx = find_listener_by_port(udp->dest);

  if (lx){

    struct socket_address src = make_socket_address(src_ip, udp->src);

    struct socket_address dst = make_socket_address(dst_ip, udp->dest);

    lx->rcvr(src, dst, payload, payload_len);

  }

}

static void

handle_icmp_packet(struct ip_addr src, struct ip_addr dst,

                   struct icmp_echo_hdr *icmp, size_t len)

{

  switch (icmp->type){

  case ICMP_DUR:        // Destinatino Unreachable

    if (icmp->code == ICMP_DUR_PORT){        // port unreachable

      //handle destination port unreachable (the host ctrl+c'd the app):

      //filter out non udp data response

      struct ip_hdr *ip = (struct ip_hdr *)(((uint8_t*)icmp) + sizeof(struct icmp_echo_hdr));

      struct udp_hdr *udp = (struct udp_hdr *)(((char *)ip) + IP_HLEN);

      if (IPH_PROTO(ip) != IP_PROTO_UDP) break;

      struct listener_entry *lx = find_listener_by_port(udp->src);

      if (lx){

        struct socket_address src = make_socket_address(ip->src, udp->src);

        struct socket_address dst = make_socket_address(ip->dest, udp->dest);

        lx->rcvr(src, dst, NULL, 0);

      }

      putchar('i');

    }

    else {

      //printf("icmp dst unr (code: %d)", icmp->code);

      putchar('i');

    }

    break;

  case ICMP_ECHO:{

    const void *icmp_data_buff = ((uint8_t*)icmp) + sizeof(struct icmp_echo_hdr);

    size_t icmp_data_len = len - sizeof(struct icmp_echo_hdr);

    struct icmp_echo_hdr echo_reply;

    echo_reply.type = 0;

    echo_reply.code = 0;

    echo_reply.chksum = 0;

    echo_reply.id = icmp->id;

    echo_reply.seqno = icmp->seqno;

    echo_reply.chksum = ~chksum_buffer( //data checksum

        (unsigned short *)icmp_data_buff,

        icmp_data_len/sizeof(short),

        chksum_buffer(                  //header checksum

            (unsigned short *)&echo_reply,

            sizeof(echo_reply)/sizeof(short),

        0)

    );

    send_ip_pkt(

        src, IP_PROTO_ICMP,

        &echo_reply, sizeof(echo_reply),

        icmp_data_buff, icmp_data_len

    );

    break;

  }

  default:

    break;

  }

}

static void

send_arp_reply(struct arp_eth_ipv4 *req, eth_mac_addr_t our_mac)

{

  struct arp_eth_ipv4 reply _AL4;

  reply.ar_hrd = req->ar_hrd;

  reply.ar_pro = req->ar_pro;

  reply.ar_hln = req->ar_hln;

  reply.ar_pln = req->ar_pln;

  reply.ar_op = ARPOP_REPLY;

  memcpy(reply.ar_sha, &our_mac, 6);

  memcpy(reply.ar_sip, req->ar_tip, 4);

  memcpy(reply.ar_tha, req->ar_sha, 6);

  memcpy(reply.ar_tip, req->ar_sip, 4);

  eth_mac_addr_t t;

  memcpy(t.addr, reply.ar_tha, 6);

  send_pkt(t, ETHERTYPE_ARP, &reply, sizeof(reply), 0, 0, 0, 0);

}

void net_common_send_arp_request(const struct ip_addr *addr){

    struct arp_eth_ipv4 req _AL4;

    req.ar_hrd = ARPHRD_ETHER;

    req.ar_pro = ETHERTYPE_IPV4;

    req.ar_hln = sizeof(eth_mac_addr_t);

    req.ar_pln = sizeof(struct ip_addr);

    req.ar_op = ARPOP_REQUEST;

    memcpy(req.ar_sha, ethernet_mac_addr(), sizeof(eth_mac_addr_t));

    memcpy(req.ar_sip, get_ip_addr(), sizeof(struct ip_addr));

    memset(req.ar_tha, 0x00, sizeof(eth_mac_addr_t));

    memcpy(req.ar_tip, addr, sizeof(struct ip_addr));

    //send the request with a broadcast ethernet mac address

    send_pkt(BCAST_MAC_ADDR, ETHERTYPE_ARP, &req, sizeof(req), 0, 0, 0, 0);

}

void send_gratuitous_arp(void){

  struct arp_eth_ipv4 req _AL4;

  req.ar_hrd = ARPHRD_ETHER;

  req.ar_pro = ETHERTYPE_IPV4;

  req.ar_hln = sizeof(eth_mac_addr_t);

  req.ar_pln = sizeof(struct ip_addr);

  req.ar_op = ARPOP_REQUEST;

  memcpy(req.ar_sha, ethernet_mac_addr(), sizeof(eth_mac_addr_t));

  memcpy(req.ar_sip, get_ip_addr(),       sizeof(struct ip_addr));

  memset(req.ar_tha, 0x00,                sizeof(eth_mac_addr_t));

  memcpy(req.ar_tip, get_ip_addr(),       sizeof(struct ip_addr));

  //send the request with a broadcast ethernet mac address

  send_pkt(BCAST_MAC_ADDR, ETHERTYPE_ARP, &req, sizeof(req), 0, 0, 0, 0);

}

static void

handle_arp_packet(struct arp_eth_ipv4 *p, size_t size)

{

  if (size < sizeof(struct arp_eth_ipv4)){

    printf("\nhandle_arp: weird size = %d\n", (int)size);

    return;

  }

  if (0){

    printf("ar_hrd = %d\n", p->ar_hrd);

    printf("ar_pro = %d\n", p->ar_pro);

    printf("ar_hln = %d\n", p->ar_hln);

    printf("ar_pln = %d\n", p->ar_pln);

    printf("ar_op  = %d\n", p->ar_op);

    printf("ar_sha = "); print_mac_addr(p->ar_sha); newline();

    printf("ar_sip = "); print_ip_addr (p->ar_sip); newline();

    printf("ar_tha = "); print_mac_addr(p->ar_tha); newline();

    printf("ar_tip = "); print_ip_addr (p->ar_tip); newline();

  }

  if (p->ar_hrd != ARPHRD_ETHER

      || p->ar_pro != ETHERTYPE_IPV4

      || p->ar_hln != 6

      || p->ar_pln != 4)

    return;

  if (p->ar_op == ARPOP_REPLY){

    struct ip_addr ip_addr;

    memcpy(&ip_addr, p->ar_sip, sizeof(ip_addr));

    eth_mac_addr_t mac_addr;

    memcpy(&mac_addr, p->ar_sha, sizeof(mac_addr));

    arp_cache_update(&ip_addr, &mac_addr);

  }

  if (p->ar_op != ARPOP_REQUEST)

    return;

  struct ip_addr sip;

  struct ip_addr tip;

  sip.addr = get_int32(p->ar_sip);

  tip.addr = get_int32(p->ar_tip);

  if (memcmp(&tip, &_local_ip_addr, sizeof(_local_ip_addr)) == 0){        // They're looking for us...

    send_arp_reply(p, _local_mac_addr);

  }

}

void

handle_eth_packet(uint32_t *p, size_t nlines)

{

  static size_t bcount = 0;

  if (debug) printf("===> %d\n", (int)bcount++);

  if (debug) print_buffer(p, nlines);

  padded_eth_hdr_t *eth_hdr = (padded_eth_hdr_t *)p;

  if (eth_hdr->ethertype == ETHERTYPE_ARP){

    struct arp_eth_ipv4 *arp = (struct arp_eth_ipv4 *)(p + 4);

    handle_arp_packet(arp, nlines*sizeof(uint32_t) - 14);

  }

  else if (eth_hdr->ethertype == ETHERTYPE_IPV4){

    struct ip_hdr *ip = (struct ip_hdr *)(p + 4);

    if (IPH_V(ip) != 4 || IPH_HL(ip) != 5)        // ignore pkts w/ bad version or options

      return;

    if (IPH_OFFSET(ip) & (IP_MF | IP_OFFMASK))        // ignore fragmented packets

      return;

    // filter on dest ip addr (should be broadcast or for us)

    bool is_bcast = memcmp(&eth_hdr->dst, &BCAST_MAC_ADDR, sizeof(BCAST_MAC_ADDR)) == 0;

    bool is_my_ip = memcmp(&ip->dest, &_local_ip_addr, sizeof(_local_ip_addr)) == 0;

    if (!is_bcast && !is_my_ip) return;

    arp_cache_update(&ip->src, (eth_mac_addr_t *)(((char *)p)+8));

    int protocol = IPH_PROTO(ip);

    int len = IPH_LEN(ip) - IP_HLEN;

    switch (protocol){

    case IP_PROTO_UDP:

      handle_udp_packet(ip->src, ip->dest, (struct udp_hdr *)(((char *)ip) + IP_HLEN), len);

      break;

    case IP_PROTO_ICMP:

      handle_icmp_packet(ip->src, ip->dest, (struct icmp_echo_hdr *)(((char *)ip) + IP_HLEN), len);

      break;

    default:        // ignore

      break;

    }

  }

  else

    return;        // Not ARP or IPV4, ignore

}