static void lease_parse_u32(const uint8_t *option, size_t len, uint32_t *ret, uint32_t min) {
assert(option);
assert(ret);
if (len == 4) {
*ret = unaligned_read_be32((be32_t*) option);
if (*ret < min)
*ret = min;
}
}
static void test_be(void) {
uint8_t scratch[16];
assert_se(unaligned_read_be16(&data[0]) == 0x0001);
assert_se(unaligned_read_be16(&data[1]) == 0x0102);
assert_se(unaligned_read_be32(&data[0]) == 0x00010203);
assert_se(unaligned_read_be32(&data[1]) == 0x01020304);
assert_se(unaligned_read_be32(&data[2]) == 0x02030405);
assert_se(unaligned_read_be32(&data[3]) == 0x03040506);
assert_se(unaligned_read_be64(&data[0]) == 0x0001020304050607);
assert_se(unaligned_read_be64(&data[1]) == 0x0102030405060708);
assert_se(unaligned_read_be64(&data[2]) == 0x0203040506070809);
assert_se(unaligned_read_be64(&data[3]) == 0x030405060708090a);
assert_se(unaligned_read_be64(&data[4]) == 0x0405060708090a0b);
assert_se(unaligned_read_be64(&data[5]) == 0x05060708090a0b0c);
assert_se(unaligned_read_be64(&data[6]) == 0x060708090a0b0c0d);
assert_se(unaligned_read_be64(&data[7]) == 0x0708090a0b0c0d0e);
zero(scratch);
unaligned_write_be16(&scratch[0], 0x0001);
assert_se(memcmp(&scratch[0], &data[0], sizeof(uint16_t)) == 0);
zero(scratch);
unaligned_write_be16(&scratch[1], 0x0102);
assert_se(memcmp(&scratch[1], &data[1], sizeof(uint16_t)) == 0);
zero(scratch);
unaligned_write_be32(&scratch[0], 0x00010203);
assert_se(memcmp(&scratch[0], &data[0], sizeof(uint32_t)) == 0);
zero(scratch);
unaligned_write_be32(&scratch[1], 0x01020304);
assert_se(memcmp(&scratch[1], &data[1], sizeof(uint32_t)) == 0);
zero(scratch);
unaligned_write_be32(&scratch[2], 0x02030405);
assert_se(memcmp(&scratch[2], &data[2], sizeof(uint32_t)) == 0);
zero(scratch);
unaligned_write_be32(&scratch[3], 0x03040506);
assert_se(memcmp(&scratch[3], &data[3], sizeof(uint32_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[0], 0x0001020304050607);
assert_se(memcmp(&scratch[0], &data[0], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[1], 0x0102030405060708);
assert_se(memcmp(&scratch[1], &data[1], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[2], 0x0203040506070809);
assert_se(memcmp(&scratch[2], &data[2], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[3], 0x030405060708090a);
assert_se(memcmp(&scratch[3], &data[3], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[4], 0x0405060708090a0b);
assert_se(memcmp(&scratch[4], &data[4], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[5], 0x05060708090a0b0c);
assert_se(memcmp(&scratch[5], &data[5], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[6], 0x060708090a0b0c0d);
assert_se(memcmp(&scratch[6], &data[6], sizeof(uint64_t)) == 0);
zero(scratch);
unaligned_write_be64(&scratch[7], 0x0708090a0b0c0d0e);
assert_se(memcmp(&scratch[7], &data[7], sizeof(uint64_t)) == 0);
}
int arp_network_bind_raw_socket(int ifindex, be32_t address, const struct ether_addr *eth_mac) {
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(struct ether_arp), 1, 0), /* packet >= arp packet ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hrd)), /* A <- header */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPHRD_ETHER, 1, 0), /* header == ethernet ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pro)), /* A <- protocol */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 1, 0), /* protocol == IP ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_hln)), /* A <- hardware address length */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct ether_addr), 1, 0), /* length == sizeof(ether_addr)? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_pln)), /* A <- protocol address length */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct in_addr), 1, 0), /* length == sizeof(in_addr) ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, ea_hdr.ar_op)), /* A <- operation */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0), /* protocol == request ? */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 1, 0), /* protocol == reply ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
/* Sender Hardware Address must be different from our own */
BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be32(ð_mac->ether_addr_octet[0])),/* 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(struct ether_arp, arp_sha)), /* A <- 4 bytes of SHA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 6), /* A == 0 ? */
BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be16(ð_mac->ether_addr_octet[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(struct ether_arp, arp_sha) + 4), /* A <- remainder of SHA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1), /* A == 0 ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
/* Sender Protocol Address or Target Protocol Address must be equal to the one we care about */
BPF_STMT(BPF_LD + BPF_IMM, htobe32(address)), /* A <- clients IP */
BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_spa)), /* A <- SPA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* X xor A */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1), /* A == 0 ? */
BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
BPF_STMT(BPF_LD + BPF_IMM, htobe32(address)), /* A <- clients IP */
BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_tpa)), /* A <- TPA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* X xor A */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 1), /* A == 0 ? */
BPF_STMT(BPF_RET + BPF_K, 65535), /* return all */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
};
struct sock_fprog fprog = {
.len = ELEMENTSOF(filter),
.filter = (struct sock_filter*) filter
};
union sockaddr_union link = {
.ll.sll_family = AF_PACKET,
.ll.sll_protocol = htobe16(ETH_P_ARP),
.ll.sll_ifindex = ifindex,
.ll.sll_halen = ETH_ALEN,
.ll.sll_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
};
_cleanup_close_ int s = -1;
int r;
assert(ifindex > 0);
s = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
if (s < 0)
return -errno;
r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
if (r < 0)
return -errno;
r = bind(s, &link.sa, sizeof(link.ll));
if (r < 0)
return -errno;
return TAKE_FD(s);
}
static int arp_send_packet(int fd, int ifindex,
be32_t pa, const struct ether_addr *ha,
bool announce) {
union sockaddr_union link = {
.ll.sll_family = AF_PACKET,
.ll.sll_protocol = htobe16(ETH_P_ARP),
.ll.sll_ifindex = ifindex,
.ll.sll_halen = ETH_ALEN,
.ll.sll_addr = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
};
struct ether_arp arp = {
.ea_hdr.ar_hrd = htobe16(ARPHRD_ETHER), /* HTYPE */
.ea_hdr.ar_pro = htobe16(ETHERTYPE_IP), /* PTYPE */
.ea_hdr.ar_hln = ETH_ALEN, /* HLEN */
.ea_hdr.ar_pln = sizeof(be32_t), /* PLEN */
.ea_hdr.ar_op = htobe16(ARPOP_REQUEST), /* REQUEST */
};
int r;
assert(fd >= 0);
assert(pa != 0);
assert(ha);
memcpy(&arp.arp_sha, ha, ETH_ALEN);
memcpy(&arp.arp_tpa, &pa, sizeof(pa));
if (announce)
memcpy(&arp.arp_spa, &pa, sizeof(pa));
r = sendto(fd, &arp, sizeof(struct ether_arp), 0, &link.sa, sizeof(link.ll));
if (r < 0)
return -errno;
return 0;
}
int arp_send_probe(int fd, int ifindex,
be32_t pa, const struct ether_addr *ha) {
return arp_send_packet(fd, ifindex, pa, ha, false);
}
int arp_send_announcement(int fd, int ifindex,
be32_t pa, const struct ether_addr *ha) {
return arp_send_packet(fd, ifindex, pa, ha, true);
}
