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/* NHRP daemon Linux specific glue
* Copyright (c) 2014-2015 Timo Teräs
*
* This file is free software: you may copy, redistribute and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*/
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <asm/types.h>
#include <arpa/inet.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/ip.h>
#include <linux/if_arp.h>
#include <linux/if_tunnel.h>
#include "nhrp_protocol.h"
#include "os.h"
#include "netlink.h"
static int nhrp_socket_fd = -1;
int os_socket(void)
{
if (nhrp_socket_fd < 0)
nhrp_socket_fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_NHRP));
return nhrp_socket_fd;
}
int os_sendmsg(const uint8_t *buf, size_t len, int ifindex, const uint8_t *addr, size_t addrlen)
{
struct sockaddr_ll lladdr;
struct iovec iov = {
.iov_base = (void*) buf,
.iov_len = len,
};
struct msghdr msg = {
.msg_name = &lladdr,
.msg_namelen = sizeof(lladdr),
.msg_iov = &iov,
.msg_iovlen = 1,
};
int status;
if (addrlen > sizeof(lladdr.sll_addr))
return -1;
memset(&lladdr, 0, sizeof(lladdr));
lladdr.sll_family = AF_PACKET;
lladdr.sll_protocol = htons(ETH_P_NHRP);
lladdr.sll_ifindex = ifindex;
lladdr.sll_halen = addrlen;
memcpy(lladdr.sll_addr, addr, addrlen);
status = sendmsg(nhrp_socket_fd, &msg, 0);
if (status < 0)
return -1;
return 0;
}
int os_recvmsg(uint8_t *buf, size_t *len, int *ifindex, uint8_t *addr, size_t *addrlen)
{
struct sockaddr_ll lladdr;
struct iovec iov = {
.iov_base = buf,
.iov_len = *len,
};
struct msghdr msg = {
.msg_name = &lladdr,
.msg_namelen = sizeof(lladdr),
.msg_iov = &iov,
.msg_iovlen = 1,
};
int r;
r = recvmsg(nhrp_socket_fd, &msg, MSG_DONTWAIT);
if (r < 0)
return r;
*len = r;
*ifindex = lladdr.sll_ifindex;
if (*addrlen <= (size_t) lladdr.sll_addr) {
if (memcmp(lladdr.sll_addr, "\x00\x00\x00\x00", 4) != 0) {
memcpy(addr, lladdr.sll_addr, lladdr.sll_halen);
*addrlen = lladdr.sll_halen;
} else {
*addrlen = 0;
}
}
return 0;
}
static int linux_configure_arp(const char *iface, int on)
{
struct ifreq ifr;
strncpy(ifr.ifr_name, iface, IFNAMSIZ);
if (ioctl(nhrp_socket_fd, SIOCGIFFLAGS, &ifr))
return -1;
if (on)
ifr.ifr_flags &= ~IFF_NOARP;
else
ifr.ifr_flags |= IFF_NOARP;
if (ioctl(nhrp_socket_fd, SIOCSIFFLAGS, &ifr))
return -1;
return 0;
}
static int linux_icmp_redirect_off(const char *iface)
{
char fname[256];
int fd, ret = -1;
sprintf(fname, "/proc/sys/net/ipv4/conf/%s/send_redirects", iface);
fd = open(fname, O_WRONLY);
if (fd < 0)
return -1;
if (write(fd, "0\n", 2) == 2)
ret = 0;
close(fd);
return ret;
}
int os_configure_dmvpn(unsigned int ifindex, const char *ifname, int af)
{
int ret = -1;
switch (af) {
case AF_INET:
ret = linux_icmp_redirect_off("all");
ret |= linux_icmp_redirect_off(ifname);
ret |= netlink_configure_arp(ifindex, AF_INET);
ret |= linux_configure_arp(ifname, 1);
break;
}
return ret;
}
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