l2_packet_linux.c

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/*
 * WPA Supplicant - Layer2 packet handling with Linux packet sockets
 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"
#include <sys/ioctl.h>
#include <netpacket/packet.h>
#include <net/if.h>

#include "common.h"
#include "eloop.h"
#include "l2_packet.h"


struct l2_packet_data {
        int fd; /* packet socket for EAPOL frames */
        char ifname[IFNAMSIZ + 1];
        int ifindex;
        u8 own_addr[ETH_ALEN];
        void (*rx_callback)(void *ctx, const u8 *src_addr,
                            const u8 *buf, size_t len);
        void *rx_callback_ctx;
        int l2_hdr; /* whether to include layer 2 (Ethernet) header data
                     * buffers */
};


int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
{
        os_memcpy(addr, l2->own_addr, ETH_ALEN);
        return 0;
}


int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
                   const u8 *buf, size_t len)
{
        int ret;
        if (l2 == NULL)
                return -1;
        if (l2->l2_hdr) {
                ret = send(l2->fd, buf, len, 0);
                if (ret < 0)
                        perror("l2_packet_send - send");
        } else {
                struct sockaddr_ll ll;
                os_memset(&ll, 0, sizeof(ll));
                ll.sll_family = AF_PACKET;
                ll.sll_ifindex = l2->ifindex;
                ll.sll_protocol = htons(proto);
                ll.sll_halen = ETH_ALEN;
                os_memcpy(ll.sll_addr, dst_addr, ETH_ALEN);
                ret = sendto(l2->fd, buf, len, 0, (struct sockaddr *) &ll,
                             sizeof(ll));
                if (ret < 0)
                        perror("l2_packet_send - sendto");
        }
        return ret;
}


static void l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
        struct l2_packet_data *l2 = eloop_ctx;
        u8 buf[2300];
        int res;
        struct sockaddr_ll ll;
        socklen_t fromlen;

        os_memset(&ll, 0, sizeof(ll));
        fromlen = sizeof(ll);
        res = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &ll,
                       &fromlen);
        if (res < 0) {
                perror("l2_packet_receive - recvfrom");
                return;
        }

        l2->rx_callback(l2->rx_callback_ctx, ll.sll_addr, buf, res);
}


struct l2_packet_data * l2_packet_init(
        const char *ifname, const u8 *own_addr, unsigned short protocol,
        void (*rx_callback)(void *ctx, const u8 *src_addr,
                            const u8 *buf, size_t len),
        void *rx_callback_ctx, int l2_hdr)
{
        struct l2_packet_data *l2;
        struct ifreq ifr;
        struct sockaddr_ll ll;

        l2 = os_zalloc(sizeof(struct l2_packet_data));
        if (l2 == NULL)
                return NULL;
        os_strlcpy(l2->ifname, ifname, sizeof(l2->ifname));
        l2->rx_callback = rx_callback;
        l2->rx_callback_ctx = rx_callback_ctx;
        l2->l2_hdr = l2_hdr;

        l2->fd = socket(PF_PACKET, l2_hdr ? SOCK_RAW : SOCK_DGRAM,
                        htons(protocol));
        if (l2->fd < 0) {
                perror("socket(PF_PACKET)");
                os_free(l2);
                return NULL;
        }
        os_memset(&ifr, 0, sizeof(ifr));
        os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name));
        if (ioctl(l2->fd, SIOCGIFINDEX, &ifr) < 0) {
                perror("ioctl[SIOCGIFINDEX]");
                close(l2->fd);
                os_free(l2);
                return NULL;
        }
        l2->ifindex = ifr.ifr_ifindex;

        os_memset(&ll, 0, sizeof(ll));
        ll.sll_family = PF_PACKET;
        ll.sll_ifindex = ifr.ifr_ifindex;
        ll.sll_protocol = htons(protocol);
        if (bind(l2->fd, (struct sockaddr *) &ll, sizeof(ll)) < 0) {
                perror("bind[PF_PACKET]");
                close(l2->fd);
                os_free(l2);
                return NULL;
        }

        if (ioctl(l2->fd, SIOCGIFHWADDR, &ifr) < 0) {
                perror("ioctl[SIOCGIFHWADDR]");
                close(l2->fd);
                os_free(l2);
                return NULL;
        }
        os_memcpy(l2->own_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);

        eloop_register_read_sock(l2->fd, l2_packet_receive, l2, NULL);

        return l2;
}


void l2_packet_deinit(struct l2_packet_data *l2)
{
        if (l2 == NULL)
                return;

        if (l2->fd >= 0) {
                eloop_unregister_read_sock(l2->fd);
                close(l2->fd);
        }
                
        os_free(l2);
}


int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
{
        int s;
        struct ifreq ifr;
        struct sockaddr_in *saddr;
        size_t res;

        s = socket(PF_INET, SOCK_DGRAM, 0);
        if (s < 0) {
                perror("socket");
                return -1;
        }
        os_memset(&ifr, 0, sizeof(ifr));
        os_strlcpy(ifr.ifr_name, l2->ifname, sizeof(ifr.ifr_name));
        if (ioctl(s, SIOCGIFADDR, &ifr) < 0) {
                if (errno != EADDRNOTAVAIL)
                        perror("ioctl[SIOCGIFADDR]");
                close(s);
                return -1;
        }
        close(s);
        saddr = aliasing_hide_typecast(&ifr.ifr_addr, struct sockaddr_in);
        if (saddr->sin_family != AF_INET)
                return -1;
        res = os_strlcpy(buf, inet_ntoa(saddr->sin_addr), len);
        if (res >= len)
                return -1;
        return 0;
}


void l2_packet_notify_auth_start(struct l2_packet_data *l2)
{
}