X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fpacket.c;h=66b42c5e1190752c39b55954c752ec9ee1dde23f;hb=f533ec876716415ed0e6ba28d13dfb6263068e82;hp=923add628e8003bf44fc04c419fd1096024ef882;hpb=6de8994440165e2f30c50d2d7c1f332d9cd649bd;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c index 923add628..66b42c5e1 100644 --- a/networking/udhcp/packet.c +++ b/networking/udhcp/packet.c @@ -1,40 +1,84 @@ /* vi: set sw=4 ts=4: */ - -#include -#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION -#include -#include -#else -#include -#include -#include -#endif - +/* + * Packet ops + * + * Rewrite by Russ Dill July 2001 + * + * Licensed under GPLv2, see file LICENSE in this source tree. + */ #include "common.h" #include "dhcpd.h" -#include "options.h" - +#include +#include +#include -void udhcp_init_header(struct dhcpMessage *packet, char type) +void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) { - memset(packet, 0, sizeof(struct dhcpMessage)); - packet->op = BOOTREQUEST; + memset(packet, 0, sizeof(*packet)); + packet->op = BOOTREQUEST; /* if client to a server */ switch (type) { case DHCPOFFER: case DHCPACK: case DHCPNAK: - packet->op = BOOTREPLY; + packet->op = BOOTREPLY; /* if server to client */ } - packet->htype = ETH_10MB; - packet->hlen = ETH_10MB_LEN; + packet->htype = 1; /* ethernet */ + packet->hlen = 6; packet->cookie = htonl(DHCP_MAGIC); - packet->options[0] = DHCP_END; - add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type); + if (DHCP_END != 0) + packet->options[0] = DHCP_END; + udhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type); } +#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2 +void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet) +{ + char buf[sizeof(packet->chaddr)*2 + 1]; + + if (dhcp_verbose < 2) + return; -/* read a packet from socket fd, return -1 on read error, -2 on packet error */ -int udhcp_recv_kernel_packet(struct dhcpMessage *packet, int fd) + bb_info_msg( + //" op %x" + //" htype %x" + " hlen %x" + //" hops %x" + " xid %x" + //" secs %x" + //" flags %x" + " ciaddr %x" + " yiaddr %x" + " siaddr %x" + " giaddr %x" + //" chaddr %s" + //" sname %s" + //" file %s" + //" cookie %x" + //" options %s" + //, packet->op + //, packet->htype + , packet->hlen + //, packet->hops + , packet->xid + //, packet->secs + //, packet->flags + , packet->ciaddr + , packet->yiaddr + , packet->siaddr_nip + , packet->gateway_nip + //, packet->chaddr[16] + //, packet->sname[64] + //, packet->file[128] + //, packet->cookie + //, packet->options[] + ); + *bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0'; + bb_info_msg(" chaddr %s", buf); +} +#endif + +/* Read a packet from socket fd, return -1 on read error, -2 on packet error */ +int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) { int bytes; unsigned char *vendor; @@ -42,18 +86,19 @@ int udhcp_recv_kernel_packet(struct dhcpMessage *packet, int fd) memset(packet, 0, sizeof(*packet)); bytes = safe_read(fd, packet, sizeof(*packet)); if (bytes < 0) { - DEBUG("cannot read on listening socket, ignoring"); + log1("Packet read error, ignoring"); return bytes; /* returns -1 */ } if (packet->cookie != htonl(DHCP_MAGIC)) { - bb_error_msg("received bogus message, ignoring"); + bb_info_msg("Packet with bad magic, ignoring"); return -2; } - DEBUG("Received a packet"); + log1("Received a packet"); + udhcp_dump_packet(packet); if (packet->op == BOOTREQUEST) { - vendor = get_option(packet, DHCP_VENDOR); + vendor = udhcp_get_option(packet, DHCP_VENDOR); if (vendor) { #if 0 static const char broken_vendors[][8] = { @@ -62,19 +107,19 @@ int udhcp_recv_kernel_packet(struct dhcpMessage *packet, int fd) }; int i; for (i = 0; broken_vendors[i][0]; i++) { - if (vendor[OPT_LEN - 2] == (uint8_t)strlen(broken_vendors[i]) - && !strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - 2]) + if (vendor[OPT_LEN - OPT_DATA] == (uint8_t)strlen(broken_vendors[i]) + && strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - OPT_DATA]) == 0 ) { - DEBUG("broken client (%s), forcing broadcast", + log1("Broken client (%s), forcing broadcast replies", broken_vendors[i]); packet->flags |= htons(BROADCAST_FLAG); } } #else - if (vendor[OPT_LEN - 2] == (uint8_t)(sizeof("MSFT 98")-1) + if (vendor[OPT_LEN - OPT_DATA] == (uint8_t)(sizeof("MSFT 98")-1) && memcmp(vendor, "MSFT 98", sizeof("MSFT 98")-1) == 0 ) { - DEBUG("broken client (%s), forcing broadcast", "MSFT 98"); + log1("Broken client (%s), forcing broadcast replies", "MSFT 98"); packet->flags |= htons(BROADCAST_FLAG); } #endif @@ -84,11 +129,10 @@ int udhcp_recv_kernel_packet(struct dhcpMessage *packet, int fd) return bytes; } - -uint16_t udhcp_checksum(void *addr, int count) +uint16_t FAST_FUNC udhcp_checksum(void *addr, int count) { /* Compute Internet Checksum for "count" bytes - * beginning at location "addr". + * beginning at location "addr". */ int32_t sum = 0; uint16_t *source = (uint16_t *) addr; @@ -114,66 +158,71 @@ uint16_t udhcp_checksum(void *addr, int count) return ~sum; } - /* Construct a ip/udp header for a packet, send packet */ -int udhcp_send_raw_packet(struct dhcpMessage *payload, - uint32_t source_ip, int source_port, - uint32_t dest_ip, int dest_port, const uint8_t *dest_arp, int ifindex) +int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt, + 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 udp_dhcp_packet packet; + 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 udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, - UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct 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)); - packet.data = *payload; /* struct copy */ + 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.sll_family = AF_PACKET; + dest_sll.sll_protocol = htons(ETH_P_IP); + dest_sll.sll_ifindex = ifindex; + dest_sll.sll_halen = 6; + memcpy(dest_sll.sll_addr, dest_arp, 6); - 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) { + 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. + */ + padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options); + 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 = udhcp_checksum(&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)); - /* Currently we send full-sized DHCP packets (zero padded). - * If you need to change this: last byte of the packet is - * packet.data.options[end_option(packet.data.options)] - */ - result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0, - (struct sockaddr *) &dest, sizeof(dest)); + udhcp_dump_packet(dhcp_pkt); + result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0, + (struct sockaddr *) &dest_sll, sizeof(dest_sll)); msg = "sendto"; ret_close: close(fd); @@ -184,21 +233,17 @@ int udhcp_send_raw_packet(struct dhcpMessage *payload, return result; } - /* Let the kernel do all the work for packet generation */ -int udhcp_send_kernel_packet(struct dhcpMessage *payload, - uint32_t source_ip, int source_port, - uint32_t dest_ip, int dest_port) +int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt, + uint32_t source_nip, int source_port, + uint32_t dest_nip, int dest_port) { struct sockaddr_in client; + unsigned padding; int fd; int result = -1; const char *msg; - enum { - DHCP_SIZE = sizeof(struct dhcpMessage) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, - }; - fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); if (fd < 0) { msg = "socket(%s)"; @@ -209,7 +254,7 @@ int udhcp_send_kernel_packet(struct dhcpMessage *payload, memset(&client, 0, sizeof(client)); client.sin_family = AF_INET; client.sin_port = htons(source_port); - client.sin_addr.s_addr = source_ip; + client.sin_addr.s_addr = source_nip; if (bind(fd, (struct sockaddr *)&client, sizeof(client)) == -1) { msg = "bind(%s)"; goto ret_close; @@ -218,14 +263,16 @@ int udhcp_send_kernel_packet(struct dhcpMessage *payload, memset(&client, 0, sizeof(client)); client.sin_family = AF_INET; client.sin_port = htons(dest_port); - client.sin_addr.s_addr = dest_ip; + client.sin_addr.s_addr = dest_nip; if (connect(fd, (struct sockaddr *)&client, sizeof(client)) == -1) { msg = "connect"; goto ret_close; } - /* Currently we send full-sized DHCP packets (see above) */ - result = safe_write(fd, payload, DHCP_SIZE); + udhcp_dump_packet(dhcp_pkt); + + padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options); + result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding); msg = "write"; ret_close: close(fd);