X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Flibsystemd-network%2Fdhcp-network.c;h=29276c0559b07a90213a95da9cb5395ff26d5b41;hb=076adf013a171e819f84684e2eb22e965e96ee59;hp=ecc94b9be782946a30d89bfcd96c2ce44e980b44;hpb=66a67effcc5beaf8a61e1c1147c3114b02a96439;p=elogind.git diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c index ecc94b9be..29276c055 100644 --- a/src/libsystemd-network/dhcp-network.c +++ b/src/libsystemd-network/dhcp-network.c @@ -23,16 +23,70 @@ #include #include #include +#include #include #include +#include #include "socket-util.h" #include "dhcp-internal.h" -int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link) -{ - int s, one = 1; +int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, + uint32_t xid, struct ether_addr mac_addr) { + struct sock_filter filter[] = { + BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), /* A <- packet length */ + BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, 0), /* packet >= DHCPPacket ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */ + BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */ + BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_PORT_CLIENT, 1, 0), /* UDP destination port == DHCP client port ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.op)), /* A <- DHCP op */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, BOOTREPLY, 1, 0), /* op == BOOTREPLY ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.htype)), /* A <- DHCP header type */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header type == ARPHRD_ETHER ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, dhcp.hlen)), /* A <- mac address length */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHER_ADDR_LEN, 1, 0), /* address length == ETHER_ADDR_LEN ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) &mac_addr))), /* A <- 4 bytes of client's MAC */ + BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */ + BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((unsigned short *) (((char *) &mac_addr) + 4)))), /* A <- remainder of client's MAC */ + BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */ + BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */ + BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.magic)), /* A <- DHCP magic cookie */ + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), /* cookie == DHCP magic cookie ? */ + BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */ + BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */ + }; + struct sock_fprog fprog = { + .len = ELEMENTSOF(filter), + .filter = filter + }; + _cleanup_close_ int s = -1; + int r, on = 1; assert(index > 0); assert(link); @@ -41,67 +95,105 @@ int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link) if (s < 0) return -errno; + r = setsockopt (s, SOL_PACKET, PACKET_AUXDATA, &on, sizeof(on)); + if (r < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog)); + if (r < 0) + return -errno; + link->ll.sll_family = AF_PACKET; link->ll.sll_protocol = htons(ETH_P_IP); link->ll.sll_ifindex = index; link->ll.sll_halen = ETH_ALEN; memset(link->ll.sll_addr, 0xff, ETH_ALEN); - if (setsockopt (s, SOL_PACKET, PACKET_AUXDATA, &one, sizeof(one)) < 0) + r = bind(s, &link->sa, sizeof(link->ll)); + if (r < 0) return -errno; - if (bind(s, &link->sa, sizeof(link->ll)) < 0) { - safe_close(s); - return -errno; - } + r = s; + s = -1; - return s; + return r; } -int dhcp_network_bind_udp_socket(int index, be32_t address, uint16_t port) -{ - int s; +int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) { union sockaddr_union src = { .in.sin_family = AF_INET, .in.sin_port = htobe16(port), .in.sin_addr.s_addr = address, }; + _cleanup_close_ int s = -1; + int r, on = 1, tos = IPTOS_CLASS_CS6; s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0); if (s < 0) return -errno; - if (bind(s, &src.sa, sizeof(src.in)) < 0) { - safe_close(s); + r = setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)); + if (r < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); + if (r < 0) return -errno; + + if (address == INADDR_ANY) { + r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on)); + if (r < 0) + return -errno; + + r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)); + if (r < 0) + return -errno; + } else { + r = setsockopt(s, IPPROTO_IP, IP_FREEBIND, &on, sizeof(on)); + if (r < 0) + return -errno; } - return s; + r = bind(s, &src.sa, sizeof(src.in)); + if (r < 0) + return -errno; + + r = s; + s = -1; + + return r; } int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link, - const void *packet, size_t len) -{ + const void *packet, size_t len) { + int r; + assert(link); assert(packet); assert(len); - if (sendto(s, packet, len, 0, &link->sa, sizeof(link->ll)) < 0) + r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll)); + if (r < 0) return -errno; return 0; } int dhcp_network_send_udp_socket(int s, be32_t address, uint16_t port, - const void *packet, size_t len) -{ + const void *packet, size_t len) { union sockaddr_union dest = { .in.sin_family = AF_INET, .in.sin_port = htobe16(port), .in.sin_addr.s_addr = address, }; + int r; + + assert(s >= 0); + assert(packet); + assert(len); - if (sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in)) < 0) + r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in)); + if (r < 0) return -errno; return 0;