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/* $OpenBSD: udpsock.c,v 1.4 2016/02/06 23:50:10 krw Exp $ */
/*
* Copyright (c) 2014 YASUOKA Masahiko <yasuoka@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h> /* nitems */
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "dhcp.h"
#include "tree.h"
#include "dhcpd.h"
void udpsock_handler (struct protocol *);
ssize_t udpsock_send_packet(struct interface_info *, struct dhcp_packet *,
size_t, struct in_addr, struct sockaddr_in *, struct hardware *);
struct udpsock {
int sock;
};
void
udpsock_startup(struct in_addr bindaddr)
{
int sock, onoff;
struct sockaddr_in sin4;
struct udpsock *udpsock;
if ((udpsock = calloc(1, sizeof(struct udpsock))) == NULL)
error("could not create udpsock: %s", strerror(errno));
memset(&sin4, 0, sizeof(sin4));
if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
error("creating a socket failed for udp: %s", strerror(errno));
onoff = 1;
if (setsockopt(sock, IPPROTO_IP, IP_RECVIF, &onoff, sizeof(onoff)) != 0)
error("setsocketopt IP_RECVIF failed for udp: %s",
strerror(errno));
if (pledge("stdio rpath inet sendfd proc id", NULL) == -1)
error("pledge: %s", strerror(errno));
sin4.sin_family = AF_INET;
sin4.sin_len = sizeof(sin4);
sin4.sin_addr = bindaddr;
sin4.sin_port = server_port;
if (bind(sock, (struct sockaddr *)&sin4, sizeof(sin4)) != 0)
error("bind failed for udp: %s", strerror(errno));
add_protocol("udp", sock, udpsock_handler, (void *)(intptr_t)udpsock);
note("Listening on %s:%d/udp.", inet_ntoa(sin4.sin_addr),
ntohs(server_port));
udpsock->sock = sock;
}
void
udpsock_handler(struct protocol *protocol)
{
int sockio;
char cbuf[256], ifname[IF_NAMESIZE];
ssize_t len;
struct udpsock *udpsock = protocol->local;
struct msghdr m;
struct cmsghdr *cm;
struct iovec iov[1];
struct sockaddr_storage ss;
struct sockaddr_in *sin4;
struct sockaddr_dl *sdl = NULL;
struct interface_info iface;
struct iaddr from, addr;
unsigned char packetbuf[4095];
struct dhcp_packet *packet = (struct dhcp_packet *)packetbuf;
struct hardware hw;
struct ifreq ifr;
struct subnet *subnet;
memset(&hw, 0, sizeof(hw));
iov[0].iov_base = packetbuf;
iov[0].iov_len = sizeof(packetbuf);
memset(&m, 0, sizeof(m));
m.msg_name = &ss;
m.msg_namelen = sizeof(ss);
m.msg_iov = iov;
m.msg_iovlen = nitems(iov);
m.msg_control = cbuf;
m.msg_controllen = sizeof(cbuf);
memset(&iface, 0, sizeof(iface));
if ((len = recvmsg(udpsock->sock, &m, 0)) < 0) {
warning("receiving a DHCP message failed: %s", strerror(errno));
return;
}
if (ss.ss_family != AF_INET) {
warning("received DHCP message is not AF_INET");
return;
}
sin4 = (struct sockaddr_in *)&ss;
for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&m);
m.msg_controllen != 0 && cm;
cm = (struct cmsghdr *)CMSG_NXTHDR(&m, cm)) {
if (cm->cmsg_level == IPPROTO_IP &&
cm->cmsg_type == IP_RECVIF)
sdl = (struct sockaddr_dl *)CMSG_DATA(cm);
}
if (sdl == NULL) {
warning("could not get the received interface by IP_RECVIF");
return;
}
if_indextoname(sdl->sdl_index, ifname);
if ((sockio = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
warning("socket creation failed: %s", strerror(errno));
return;
}
strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(sockio, SIOCGIFADDR, &ifr, sizeof(ifr)) != 0) {
warning("Failed to get address for %s: %s", ifname,
strerror(errno));
close(sockio);
return;
}
close(sockio);
if (ifr.ifr_addr.sa_family != AF_INET)
return;
iface.is_udpsock = 1;
iface.send_packet = udpsock_send_packet;
iface.wfdesc = udpsock->sock;
iface.ifp = 𝔦
iface.index = sdl->sdl_index;
iface.primary_address = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;
strlcpy(iface.name, ifname, sizeof(iface.name));
addr.len = 4;
memcpy(&addr.iabuf, &iface.primary_address, addr.len);
if ((subnet = find_subnet(addr)) == NULL)
return;
iface.shared_network = subnet->shared_network ;
from.len = 4;
memcpy(&from.iabuf, &sin4->sin_addr, from.len);
do_packet(&iface, packet, len, sin4->sin_port, from, &hw);
}
ssize_t
udpsock_send_packet(struct interface_info *interface, struct dhcp_packet *raw,
size_t len, struct in_addr from, struct sockaddr_in *to,
struct hardware *hto)
{
return (sendto(interface->wfdesc, raw, len, 0, (struct sockaddr *)to,
sizeof(struct sockaddr_in)));
}
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