X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fpacket.c;h=64af802a34c5c2cf3436fd4d6d5d19e1679ac384;hb=253c4e787a799a3e1f92957ed791b5222f8d2f64;hp=ecdbec7f3f51f443f35d314e600d11e56c8c7b19;hpb=7724c766bdfba5f3af5cdf5d869bcf03f45149e3;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c index ecdbec7f3..64af802a3 100644 --- a/networking/udhcp/packet.c +++ b/networking/udhcp/packet.c @@ -1,23 +1,18 @@ /* vi: set sw=4 ts=4: */ /* - * packet.c -- packet ops + * Packet ops + * * Rewrite by Russ Dill July 2001 * - * Licensed under GPLv2, see file LICENSE in this tarball for details. + * Licensed under GPLv2, see file LICENSE in this source tree. */ -#include -#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION -#include -#include -#else -#include -#include -#include -#endif - #include "common.h" #include "dhcpd.h" +#include +#include +#include +#if ENABLE_UDHCPC || ENABLE_UDHCPD void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) { memset(packet, 0, sizeof(*packet)); @@ -35,6 +30,7 @@ void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) packet->options[0] = DHCP_END; udhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type); } +#endif #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2 void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet) @@ -56,7 +52,6 @@ void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet) " yiaddr %x" " siaddr %x" " giaddr %x" - //" chaddr %s" //" sname %s" //" file %s" //" cookie %x" @@ -72,7 +67,6 @@ void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet) , packet->yiaddr , packet->siaddr_nip , packet->gateway_nip - //, packet->chaddr[16] //, packet->sname[64] //, packet->file[128] //, packet->cookie @@ -87,148 +81,104 @@ void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet) int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) { int bytes; - unsigned char *vendor; memset(packet, 0, sizeof(*packet)); bytes = safe_read(fd, packet, sizeof(*packet)); if (bytes < 0) { - log1("Packet read error, ignoring"); + log1("packet read error, ignoring"); return bytes; /* returns -1 */ } - if (packet->cookie != htonl(DHCP_MAGIC)) { - bb_info_msg("Packet with bad magic, ignoring"); + if (bytes < offsetof(struct dhcp_packet, options) + || packet->cookie != htonl(DHCP_MAGIC) + ) { + bb_info_msg("packet with bad magic, ignoring"); return -2; } - log1("Received a packet"); + log1("received %s", "a packet"); udhcp_dump_packet(packet); - if (packet->op == BOOTREQUEST) { - vendor = udhcp_get_option(packet, DHCP_VENDOR); - if (vendor) { -#if 0 - static const char broken_vendors[][8] = { - "MSFT 98", - "" - }; - int i; - for (i = 0; broken_vendors[i][0]; i++) { - if (vendor[OPT_LEN - OPT_DATA] == (uint8_t)strlen(broken_vendors[i]) - && strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - OPT_DATA]) == 0 - ) { - log1("Broken client (%s), forcing broadcast replies", - broken_vendors[i]); - packet->flags |= htons(BROADCAST_FLAG); - } - } -#else - if (vendor[OPT_LEN - OPT_DATA] == (uint8_t)(sizeof("MSFT 98")-1) - && memcmp(vendor, "MSFT 98", sizeof("MSFT 98")-1) == 0 - ) { - log1("Broken client (%s), forcing broadcast replies", "MSFT 98"); - packet->flags |= htons(BROADCAST_FLAG); - } -#endif - } - } - return bytes; } -uint16_t FAST_FUNC udhcp_checksum(void *addr, int count) -{ - /* Compute Internet Checksum for "count" bytes - * beginning at location "addr". - */ - int32_t sum = 0; - uint16_t *source = (uint16_t *) addr; - - while (count > 1) { - /* This is the inner loop */ - sum += *source++; - count -= 2; - } - - /* Add left-over byte, if any */ - if (count > 0) { - /* Make sure that the left-over byte is added correctly both - * with little and big endian hosts */ - uint16_t tmp = 0; - *(uint8_t*)&tmp = *(uint8_t*)source; - sum += tmp; - } - /* Fold 32-bit sum to 16 bits */ - while (sum >> 16) - sum = (sum & 0xffff) + (sum >> 16); - - return ~sum; -} - /* Construct a ip/udp header for a packet, send packet */ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, - uint32_t source_ip, int source_port, - uint32_t dest_ip, int dest_port, const uint8_t *dest_arp, + uint32_t source_nip, int source_port, + uint32_t dest_nip, int dest_port, const uint8_t *dest_arp, int ifindex) { - struct sockaddr_ll dest; + struct sockaddr_ll dest_sll; struct ip_udp_dhcp_packet packet; + unsigned padding; int fd; int result = -1; const char *msg; - enum { - IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, - UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct ip_udp_dhcp_packet, udp), - }; - fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP)); if (fd < 0) { msg = "socket(%s)"; goto ret_msg; } - memset(&dest, 0, sizeof(dest)); - memset(&packet, 0, sizeof(packet)); + memset(&dest_sll, 0, sizeof(dest_sll)); + memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data)); packet.data = *dhcp_pkt; /* struct copy */ - dest.sll_family = AF_PACKET; - dest.sll_protocol = htons(ETH_P_IP); - dest.sll_ifindex = ifindex; - dest.sll_halen = 6; - memcpy(dest.sll_addr, dest_arp, 6); - if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) { + dest_sll.sll_family = AF_PACKET; + dest_sll.sll_protocol = htons(ETH_P_IP); + dest_sll.sll_ifindex = ifindex; + /*dest_sll.sll_hatype = ARPHRD_???;*/ + /*dest_sll.sll_pkttype = PACKET_???;*/ + 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; } + /* We were sending full-sized DHCP packets (zero padded), + * but some badly configured servers were seen dropping them. + * Apparently they drop all DHCP packets >576 *ethernet* octets big, + * whereas they may only drop packets >576 *IP* octets big + * (which for typical Ethernet II means 590 octets: 6+6+2 + 576). + * + * In order to work with those buggy servers, + * we truncate packets after end option byte. + * + * However, RFC 1542 says "The IP Total Length and UDP Length + * must be large enough to contain the minimal BOOTP header of 300 octets". + * Thus, we retain enough padding to not go below 300 BOOTP bytes. + * Some devices have filters which drop DHCP packets shorter than that. + */ + padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options); + if (padding > DHCP_SIZE - 300) + padding = DHCP_SIZE - 300; + packet.ip.protocol = IPPROTO_UDP; - packet.ip.saddr = source_ip; - packet.ip.daddr = dest_ip; + packet.ip.saddr = source_nip; + packet.ip.daddr = dest_nip; packet.udp.source = htons(source_port); packet.udp.dest = htons(dest_port); /* size, excluding IP header: */ - packet.udp.len = htons(UPD_DHCP_SIZE); + packet.udp.len = htons(UDP_DHCP_SIZE - padding); /* for UDP checksumming, ip.len is set to UDP packet len */ packet.ip.tot_len = packet.udp.len; - packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE); + packet.udp.check = inet_cksum((uint16_t *)&packet, + IP_UDP_DHCP_SIZE - padding); /* but for sending, it is set to IP packet len */ - packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE); + packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding); packet.ip.ihl = sizeof(packet.ip) >> 2; packet.ip.version = IPVERSION; packet.ip.ttl = IPDEFTTL; - packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip)); + packet.ip.check = inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip)); - /* Currently we send full-sized DHCP packets (zero padded). - * If you need to change this: last byte of the packet is - * packet.data.options[udhcp_end_option(packet.data.options)] - */ udhcp_dump_packet(dhcp_pkt); - result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0, - (struct sockaddr *) &dest, sizeof(dest)); + result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0, + (struct sockaddr *) &dest_sll, sizeof(dest_sll)); msg = "sendto"; ret_close: close(fd); - /* FIXME: and if result >= 0 but != IP_UPD_DHCP_SIZE? */ if (result < 0) { ret_msg: bb_perror_msg(msg, "PACKET"); @@ -238,18 +188,15 @@ int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, /* Let the kernel do all the work for packet generation */ int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt, - uint32_t source_ip, int source_port, - uint32_t dest_ip, int dest_port) + uint32_t source_nip, int source_port, + uint32_t dest_nip, int dest_port) { - struct sockaddr_in client; + struct sockaddr_in sa; + unsigned padding; int fd; int result = -1; const char *msg; - enum { - DHCP_SIZE = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, - }; - fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); if (fd < 0) { msg = "socket(%s)"; @@ -257,31 +204,32 @@ int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt, } setsockopt_reuseaddr(fd); - memset(&client, 0, sizeof(client)); - client.sin_family = AF_INET; - client.sin_port = htons(source_port); - client.sin_addr.s_addr = source_ip; - if (bind(fd, (struct sockaddr *)&client, sizeof(client)) == -1) { + memset(&sa, 0, sizeof(sa)); + sa.sin_family = AF_INET; + sa.sin_port = htons(source_port); + sa.sin_addr.s_addr = source_nip; + if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) { msg = "bind(%s)"; goto ret_close; } - memset(&client, 0, sizeof(client)); - client.sin_family = AF_INET; - client.sin_port = htons(dest_port); - client.sin_addr.s_addr = dest_ip; - if (connect(fd, (struct sockaddr *)&client, sizeof(client)) == -1) { + memset(&sa, 0, sizeof(sa)); + sa.sin_family = AF_INET; + sa.sin_port = htons(dest_port); + sa.sin_addr.s_addr = dest_nip; + if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) { msg = "connect"; goto ret_close; } - /* Currently we send full-sized DHCP packets (see above) */ udhcp_dump_packet(dhcp_pkt); - result = safe_write(fd, dhcp_pkt, DHCP_SIZE); + padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options); + if (padding > DHCP_SIZE - 300) + padding = DHCP_SIZE - 300; + result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding); msg = "write"; ret_close: close(fd); - /* FIXME: and if result >= 0 but != DHCP_SIZE? */ if (result < 0) { ret_msg: bb_perror_msg(msg, "UDP");