Subject: Explicitly set DHCP_MAX_SIZE (option 57) for request packets, like for discover. function old new delta init_packet 276 368 +92 udhcp_read_interface 428 500 +72 udhcpc_main 3808 3848 +40 .rodata 83794 83806 +12 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 4/0 up/down: 216/0) Total: 216 bytes Signed-off-by: Vladislav Grishenko --- busybox.orig/networking/udhcp/common.h 2010-10-13 00:00:00.000000000 +0000 +++ busybox/networking/udhcp/common.h 2010-10-13 19:10:29.684347002 +0000 @@ -63,14 +63,14 @@ struct udp_dhcp_packet { } PACKED; enum { - IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, + IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, DHCP_SIZE = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS, }; /* Let's see whether compiler understood us right */ struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet { - char c[IP_UPD_DHCP_SIZE == 576 ? 1 : -1]; + char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1]; }; @@ -294,7 +294,7 @@ void udhcp_sp_setup(void) FAST_FUNC; int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC; int udhcp_sp_read(const fd_set *rfds) FAST_FUNC; -int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC; +int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac, uint16_t *mtu) FAST_FUNC; int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC; --- busybox.orig/networking/udhcp/dhcpc.c 2010-10-13 19:03:43.534347002 +0000 +++ busybox/networking/udhcp/dhcpc.c 2010-10-13 19:52:03.864347002 +0000 @@ -343,6 +343,8 @@ static ALWAYS_INLINE uint32_t random_xid /* Initialize the packet with the proper defaults */ static void init_packet(struct dhcp_packet *packet, char type) { + int max_packet = sizeof(struct ip_udp_dhcp_packet); + udhcp_init_header(packet, type); memcpy(packet->chaddr, client_config.client_mac, 6); if (client_config.clientid) @@ -357,6 +359,16 @@ static void init_packet(struct dhcp_pack ) { udhcp_add_binary_option(packet, client_config.vendorclass); } + switch (type) { + case DHCPDISCOVER: + /* Explicitly saying that we want RFC-compliant packets helps + * some buggy DHCP servers to NOT send bigger packets */ + max_packet = IP_UDP_DHCP_SIZE; + /* Fall through */ + case DHCPREQUEST: + if (max_packet < client_config.client_mtu) + udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(max_packet)); + } } static void add_client_options(struct dhcp_packet *packet) @@ -433,9 +445,6 @@ static int send_discover(uint32_t xid, u packet.xid = xid; if (requested) udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested); - /* Explicitly saying that we want RFC-compliant packets helps - * some buggy DHCP servers to NOT send bigger packets */ - udhcp_add_simple_option(&packet, DHCP_MAX_SIZE, htons(576)); add_client_options(&packet); bb_info_msg("Sending discover..."); @@ -923,7 +932,8 @@ int udhcpc_main(int argc UNUSED_PARAM, c if (udhcp_read_interface(client_config.interface, &client_config.ifindex, NULL, - client_config.client_mac) + client_config.client_mac, + &client_config.client_mtu) ) { return 1; } @@ -978,6 +988,16 @@ int udhcpc_main(int argc UNUSED_PARAM, c /* silence "uninitialized!" warning */ unsigned timestamp_before_wait = timestamp_before_wait; + /* When running on a bridge, the ifindex may have changed (e.g. if + * member interfaces were added/removed or if the status of the + * bridge changed). Interface mtu may have changed also. + * Workaround: refresh it here before processing the next packet */ + udhcp_read_interface(client_config.interface, + &client_config.ifindex, + NULL, + client_config.client_mac, + &client_config.client_mtu); + //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode); /* Was opening raw or udp socket here --- busybox.orig/networking/udhcp/dhcpc.h 2010-10-09 19:57:14.000000000 +0000 +++ busybox/networking/udhcp/dhcpc.h 2010-10-13 18:20:36.324347002 +0000 @@ -9,6 +9,7 @@ PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDD struct client_config_t { uint8_t client_mac[6]; /* Our mac address */ + uint16_t client_mtu; /* Our mtu */ char no_default_options; /* Do not include default options in request */ IF_FEATURE_UDHCP_PORT(uint16_t port;) int ifindex; /* Index number of the interface to use */ --- busybox.orig/networking/udhcp/dhcpd.c 2010-09-16 23:05:35.000000000 +0000 +++ busybox/networking/udhcp/dhcpd.c 2010-10-13 18:19:07.024347002 +0000 @@ -357,7 +357,8 @@ int udhcpd_main(int argc UNUSED_PARAM, c if (udhcp_read_interface(server_config.interface, &server_config.ifindex, &server_config.server_nip, - server_config.server_mac) + server_config.server_mac, + NULL) ) { retval = 1; goto ret; --- busybox.orig/networking/udhcp/dhcprelay.c 2010-10-09 19:57:14.000000000 +0000 +++ busybox/networking/udhcp/dhcprelay.c 2010-10-13 18:19:07.024347002 +0000 @@ -267,7 +267,7 @@ int dhcprelay_main(int argc, char **argv max_socket = init_sockets(client_ifaces, num_sockets, argv[2], fds); /* Get our IP on server_iface */ - if (udhcp_read_interface(argv[2], NULL, &our_nip, NULL)) + if (udhcp_read_interface(argv[2], NULL, &our_nip, NULL, NULL)) return 1; /* Main loop */ @@ -304,7 +304,7 @@ int dhcprelay_main(int argc, char **argv /* Get our IP on corresponding client_iface */ //why? what if server can't route such IP? - if (udhcp_read_interface(client_ifaces[i-1], NULL, &dhcp_msg.gateway_nip, NULL)) { + if (udhcp_read_interface(client_ifaces[i-1], NULL, &dhcp_msg.gateway_nip, NULL, NULL)) { /* Fall back to our server_iface's IP */ //this makes more sense! dhcp_msg.gateway_nip = our_nip; --- busybox.orig/networking/udhcp/packet.c 2010-07-25 19:15:32.000000000 +0000 +++ busybox/networking/udhcp/packet.c 2010-10-13 19:11:15.334347002 +0000 @@ -225,16 +225,16 @@ int FAST_FUNC udhcp_send_raw_packet(stru packet.udp.len = htons(UPD_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 - padding); + 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 - padding); + 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)); udhcp_dump_packet(dhcp_pkt); - result = sendto(fd, &packet, IP_UPD_DHCP_SIZE - padding, /*flags:*/ 0, + result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0, (struct sockaddr *) &dest_sll, sizeof(dest_sll)); msg = "sendto"; ret_close: --- busybox.orig/networking/udhcp/socket.c 2010-09-16 23:05:35.000000000 +0000 +++ busybox/networking/udhcp/socket.c 2010-10-13 18:19:07.024347002 +0000 @@ -34,7 +34,7 @@ #include "common.h" -int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) +int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac, uint16_t *mtu) { int fd; struct ifreq ifr; @@ -76,6 +76,15 @@ int FAST_FUNC udhcp_read_interface(const mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]); } + if (mtu) { + if (ioctl_or_warn(fd, SIOCGIFMTU, &ifr) != 0) { + close(fd); + return -1; + } + log1("Adapter mtu %d", ifr.ifr_mtu); + *mtu = ifr.ifr_mtu; + } + close(fd); return 0; }