X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fudhcp%2Fpacket.c;h=66b42c5e1190752c39b55954c752ec9ee1dde23f;hb=f533ec876716415ed0e6ba28d13dfb6263068e82;hp=4c72d7a6300a5ce68fd8b34552279e0183245976;hpb=7a76eba1f6711ed64902f7b20277b0a2d1645062;p=oweals%2Fbusybox.git diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c index 4c72d7a63..66b42c5e1 100644 --- a/networking/udhcp/packet.c +++ b/networking/udhcp/packet.c @@ -1,27 +1,20 @@ /* 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 "options.h" +#include +#include +#include void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) { - memset(packet, 0, sizeof(struct dhcp_packet)); + memset(packet, 0, sizeof(*packet)); packet->op = BOOTREQUEST; /* if client to a server */ switch (type) { case DHCPOFFER: @@ -29,11 +22,12 @@ void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type) case DHCPNAK: 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 @@ -53,7 +47,7 @@ void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet) //" secs %x" //" flags %x" " ciaddr %x" - " yiaddr %x" + " yiaddr %x" " siaddr %x" " giaddr %x" //" chaddr %s" @@ -104,7 +98,7 @@ int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) 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] = { @@ -113,8 +107,8 @@ int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *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 ) { log1("Broken client (%s), forcing broadcast replies", broken_vendors[i]); @@ -122,7 +116,7 @@ int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) } } #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 ) { log1("Broken client (%s), forcing broadcast replies", "MSFT 98"); @@ -166,65 +160,69 @@ uint16_t FAST_FUNC udhcp_checksum(void *addr, int count) /* 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_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. + */ + 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)] - */ 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); @@ -237,18 +235,15 @@ 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; + 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)"; @@ -259,7 +254,7 @@ int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt, 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; @@ -268,15 +263,16 @@ int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt, 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) */ udhcp_dump_packet(dhcp_pkt); - result = safe_write(fd, dhcp_pkt, DHCP_SIZE); + + 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);