6884f665b
Denis Vlasenko
2007-11-23
Subject
dhcp: stop using magic constants; use (htonl(CONST) != a) - it's smaller
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Commit Diff GitHub →
networking/udhcp/clientpacket.c +4 -4networking/udhcp/common.h +7 -1networking/udhcp/options.c +10 -8networking/udhcp/options.h +1 -1networking/udhcp/packet.c +1 -5
networking/udhcp/clientpacket.c+4 -4
| @@ -171,7 +171,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd) | |
| bytes = read(fd, &packet, sizeof(struct udp_dhcp_packet)); | |
| if (bytes < 0) { | |
| DEBUG("Cannot read on raw listening socket - ignoring"); | |
| - | usleep(500000); /* possible down interface, looping condition */ |
| + | sleep(1); /* possible down interface, looping condition */ |
| return -1; | |
| } | |
| @@ -190,7 +190,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd) | |
| /* Make sure its the right packet for us, and that it passes sanity checks */ | |
| if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION | |
| - | || packet.ip.ihl != sizeof(packet.ip) >> 2 |
| + | || packet.ip.ihl != (sizeof(packet.ip) >> 2) |
| || packet.udp.dest != htons(CLIENT_PORT) | |
| || bytes > (int) sizeof(struct udp_dhcp_packet) | |
| || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip)) | |
| @@ -207,7 +207,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd) | |
| return -1; | |
| } | |
| - | /* verify the UDP checksum by replacing the header with a psuedo header */ |
| + | /* verify the UDP checksum by replacing the header with a pseudo header */ |
| source = packet.ip.saddr; | |
| dest = packet.ip.daddr; | |
| check = packet.udp.check; | |
| @@ -225,7 +225,7 @@ int get_raw_packet(struct dhcpMessage *payload, int fd) | |
| memcpy(payload, &(packet.data), bytes - (sizeof(packet.ip) + sizeof(packet.udp))); | |
| - | if (ntohl(payload->cookie) != DHCP_MAGIC) { |
| + | if (payload->cookie != htonl(DHCP_MAGIC)) { |
| bb_error_msg("received bogus message (bad magic) - ignoring"); | |
| return -2; | |
| } | |
networking/udhcp/common.h+7 -1
| @@ -38,12 +38,18 @@ struct dhcpMessage { | |
| uint8_t file[128]; | |
| uint32_t cookie; | |
| uint8_t options[308]; /* 312 - cookie */ | |
| - | }; |
| + | } ATTRIBUTE_PACKED; |
| struct udp_dhcp_packet { | |
| struct iphdr ip; | |
| struct udphdr udp; | |
| struct dhcpMessage data; | |
| + | } ATTRIBUTE_PACKED; |
| + | |
| + | /* Let's see whether compiler understood us right */ |
| + | struct BUG_bad_sizeof_struct_udp_dhcp_packet { |
| + | char BUG_bad_sizeof_struct_udp_dhcp_packet |
| + | [sizeof(struct udp_dhcp_packet) != 576 ? -1 : 1]; |
| }; | |
| void udhcp_init_header(struct dhcpMessage *packet, char type); | |
networking/udhcp/options.c+10 -8
| @@ -73,12 +73,13 @@ uint8_t *get_option(struct dhcpMessage *packet, int code) | |
| { | |
| int i, length; | |
| uint8_t *optionptr; | |
| - | int over = 0, done = 0, curr = OPTION_FIELD; |
| + | int over = 0; |
| + | int curr = OPTION_FIELD; |
| optionptr = packet->options; | |
| i = 0; | |
| - | length = 308; |
| - | while (!done) { |
| + | length = sizeof(packet->options); |
| + | while (1) { |
| if (i >= length) { | |
| bb_error_msg("bogus packet, option fields too long"); | |
| return NULL; | |
| @@ -103,17 +104,18 @@ uint8_t *get_option(struct dhcpMessage *packet, int code) | |
| i += optionptr[OPT_LEN] + 2; | |
| break; | |
| case DHCP_END: | |
| - | if (curr == OPTION_FIELD && over & FILE_FIELD) { |
| + | if (curr == OPTION_FIELD && (over & FILE_FIELD)) { |
| optionptr = packet->file; | |
| i = 0; | |
| - | length = 128; |
| + | length = sizeof(packet->file); |
| curr = FILE_FIELD; | |
| - | } else if (curr == FILE_FIELD && over & SNAME_FIELD) { |
| + | } else if (curr == FILE_FIELD && (over & SNAME_FIELD)) { |
| optionptr = packet->sname; | |
| i = 0; | |
| - | length = 64; |
| + | length = sizeof(packet->sname); |
| curr = SNAME_FIELD; | |
| - | } else done = 1; |
| + | } else |
| + | return NULL; |
| break; | |
| default: | |
| i += optionptr[OPT_LEN + i] + 2; | |
networking/udhcp/options.h+1 -1
| @@ -6,7 +6,7 @@ | |
| #define TYPE_MASK 0x0F | |
| enum { | |
| - | OPTION_IP=1, |
| + | OPTION_IP = 1, |
| OPTION_IP_PAIR, | |
| OPTION_STRING, | |
| #if ENABLE_FEATURE_RFC3397 | |
networking/udhcp/packet.c+1 -5
| @@ -57,7 +57,7 @@ int udhcp_get_packet(struct dhcpMessage *packet, int fd) | |
| return -1; | |
| } | |
| - | if (ntohl(packet->cookie) != DHCP_MAGIC) { |
| + | if (packet->cookie != htonl(DHCP_MAGIC)) { |
| bb_error_msg("received bogus message, ignoring"); | |
| return -2; | |
| } | |
| @@ -123,7 +123,6 @@ uint16_t udhcp_checksum(void *addr, int count) | |
| /* Construct a ip/udp header for a packet, and specify the source and dest hardware address */ | |
| - | void BUG_sizeof_struct_udp_dhcp_packet_must_be_576(void); |
| int udhcp_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) | |
| @@ -169,9 +168,6 @@ int udhcp_raw_packet(struct dhcpMessage *payload, | |
| packet.ip.ttl = IPDEFTTL; | |
| packet.ip.check = udhcp_checksum(&(packet.ip), sizeof(packet.ip)); | |
| - | if (sizeof(struct udp_dhcp_packet) != 576) |
| - | BUG_sizeof_struct_udp_dhcp_packet_must_be_576(); |
| - | |
| result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0, | |
| (struct sockaddr *) &dest, sizeof(dest)); | |
| if (result <= 0) { | |