diff options
Diffstat (limited to 'networking/udhcp/d6_packet.c')
| -rw-r--r-- | networking/udhcp/d6_packet.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/networking/udhcp/d6_packet.c b/networking/udhcp/d6_packet.c new file mode 100644 index 0000000..3a1bb3d --- /dev/null +++ b/networking/udhcp/d6_packet.c @@ -0,0 +1,168 @@ +/* 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; + /* UDP checksum skips first four bytes of IP header. + * IPv6 'hop limit' field should be 0. + * 'next header' field should be summed as if it is in a different + * position, therefore we write its value into ip6_hlim: + */ + 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 = 8; + 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; +} |