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/* vi: set sw=4 ts=4: */
/*
* Copyright (C) 2011 Denys Vlasenko.
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include "common.h"
#include "d6_common.h"
#include "dhcpd.h"
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netpacket/packet.h>
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
void FAST_FUNC d6_dump_packet(struct d6_packet *packet)
{
if (dhcp_verbose < 2)
return;
bb_info_msg(
" xid %x"
, packet->d6_xid32
);
//*bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0';
//bb_info_msg(" chaddr %s", buf);
}
#endif
int FAST_FUNC d6_recv_kernel_packet(struct in6_addr *peer_ipv6
UNUSED_PARAM
, struct d6_packet *packet, int fd)
{
int bytes;
memset(packet, 0, sizeof(*packet));
bytes = safe_read(fd, packet, sizeof(*packet));
if (bytes < 0) {
log1("Packet read error, ignoring");
return bytes; /* returns -1 */
}
if (bytes < offsetof(struct d6_packet, d6_options)) {
bb_info_msg("Packet with bad magic, ignoring");
return -2;
}
log1("Received a packet");
d6_dump_packet(packet);
return bytes;
}
/* Construct a ipv6+udp header for a packet, send packet */
int FAST_FUNC d6_send_raw_packet(
struct d6_packet *d6_pkt, unsigned d6_pkt_size,
struct in6_addr *src_ipv6, int source_port,
struct in6_addr *dst_ipv6, int dest_port, const uint8_t *dest_arp,
int ifindex)
{
struct sockaddr_ll dest_sll;
struct ip6_udp_d6_packet packet;
int fd;
int result = -1;
const char *msg;
fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
if (fd < 0) {
msg = "socket(%s)";
goto ret_msg;
}
memset(&dest_sll, 0, sizeof(dest_sll));
memset(&packet, 0, offsetof(struct ip6_udp_d6_packet, data));
packet.data = *d6_pkt; /* struct copy */
dest_sll.sll_family = AF_PACKET;
dest_sll.sll_protocol = htons(ETH_P_IPV6);
dest_sll.sll_ifindex = ifindex;
dest_sll.sll_halen = 6;
memcpy(dest_sll.sll_addr, dest_arp, 6);
if (bind(fd, (struct sockaddr *)&dest_sll, sizeof(dest_sll)) < 0) {
msg = "bind(%s)";
goto ret_close;
}
packet.ip6.ip6_vfc = (6 << 4); /* 4 bits version, top 4 bits of tclass */
if (src_ipv6)
packet.ip6.ip6_src = *src_ipv6; /* struct copy */
packet.ip6.ip6_dst = *dst_ipv6; /* struct copy */
packet.udp.source = htons(source_port);
packet.udp.dest = htons(dest_port);
/* size, excluding IP header: */
packet.udp.len = htons(sizeof(struct udphdr) + d6_pkt_size);
packet.ip6.ip6_plen = packet.udp.len;
/*
* Someone was smoking weed (at least) while inventing UDP checksumming:
* UDP checksum skips first four bytes of IPv6 header.
* 'next header' field should be summed as if it is one more byte
* to the right, therefore we write its value (IPPROTO_UDP)
* into ip6_hlim, and its 'real' location remains zero-filled for now.
*/
packet.ip6.ip6_hlim = IPPROTO_UDP;
packet.udp.check = inet_cksum(
(uint16_t *)&packet + 2,
offsetof(struct ip6_udp_d6_packet, data) - 4 + d6_pkt_size
);
/* fix 'hop limit' and 'next header' after UDP checksumming */
packet.ip6.ip6_hlim = 1; /* observed Windows machines to use hlim=1 */
packet.ip6.ip6_nxt = IPPROTO_UDP;
d6_dump_packet(d6_pkt);
result = sendto(fd, &packet, offsetof(struct ip6_udp_d6_packet, data) + d6_pkt_size,
/*flags:*/ 0,
(struct sockaddr *) &dest_sll, sizeof(dest_sll)
);
msg = "sendto";
ret_close:
close(fd);
if (result < 0) {
ret_msg:
bb_perror_msg(msg, "PACKET");
}
return result;
}
/* Let the kernel do all the work for packet generation */
int FAST_FUNC d6_send_kernel_packet(
struct d6_packet *d6_pkt, unsigned d6_pkt_size,
struct in6_addr *src_ipv6, int source_port,
struct in6_addr *dst_ipv6, int dest_port)
{
struct sockaddr_in6 sa;
int fd;
int result = -1;
const char *msg;
fd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
if (fd < 0) {
msg = "socket(%s)";
goto ret_msg;
}
setsockopt_reuseaddr(fd);
memset(&sa, 0, sizeof(sa));
sa.sin6_family = AF_INET6;
sa.sin6_port = htons(source_port);
sa.sin6_addr = *src_ipv6; /* struct copy */
if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
msg = "bind(%s)";
goto ret_close;
}
memset(&sa, 0, sizeof(sa));
sa.sin6_family = AF_INET6;
sa.sin6_port = htons(dest_port);
sa.sin6_addr = *dst_ipv6; /* struct copy */
if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
msg = "connect";
goto ret_close;
}
d6_dump_packet(d6_pkt);
result = safe_write(fd, d6_pkt, d6_pkt_size);
msg = "write";
ret_close:
close(fd);
if (result < 0) {
ret_msg:
bb_perror_msg(msg, "UDP");
}
return result;
}
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