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-rw-r--r--src/libsystemd-network/dhcp-network.c230
1 files changed, 230 insertions, 0 deletions
diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c
new file mode 100644
index 0000000..0e5b414
--- /dev/null
+++ b/src/libsystemd-network/dhcp-network.c
@@ -0,0 +1,230 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/***
+ Copyright © 2013 Intel Corporation. All rights reserved.
+***/
+
+#include <errno.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <linux/filter.h>
+#include <linux/if_infiniband.h>
+#include <linux/if_packet.h>
+
+#include "dhcp-internal.h"
+#include "fd-util.h"
+#include "socket-util.h"
+#include "unaligned.h"
+
+static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
+ uint32_t xid, const uint8_t *mac_addr,
+ size_t mac_addr_len,
+ const uint8_t *bcast_addr,
+ const struct ether_addr *eth_mac,
+ uint16_t arp_type, uint8_t dhcp_hlen,
+ uint16_t port) {
+ 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, port, 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, arp_type, 1, 0), /* header type == arp_type ? */
+ 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, dhcp_hlen, 1, 0), /* address length == dhcp_hlen ? */
+ 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, unaligned_read_be32(&eth_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(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, unaligned_read_be16(&eth_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(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;
+
+ assert(ifindex > 0);
+ assert(link);
+
+ s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+ if (s < 0)
+ return -errno;
+
+ r = setsockopt_int(s, SOL_PACKET, PACKET_AUXDATA, true);
+ if (r < 0)
+ return r;
+
+ r = setsockopt(s, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
+ if (r < 0)
+ return -errno;
+
+ link->ll = (struct sockaddr_ll) {
+ .sll_family = AF_PACKET,
+ .sll_protocol = htobe16(ETH_P_IP),
+ .sll_ifindex = ifindex,
+ .sll_hatype = htobe16(arp_type),
+ .sll_halen = mac_addr_len,
+ };
+ memcpy(link->ll.sll_addr, bcast_addr, mac_addr_len);
+
+ r = bind(s, &link->sa, SOCKADDR_LL_LEN(link->ll));
+ if (r < 0)
+ return -errno;
+
+ return TAKE_FD(s);
+}
+
+int dhcp_network_bind_raw_socket(int ifindex, union sockaddr_union *link,
+ uint32_t xid, const uint8_t *mac_addr,
+ size_t mac_addr_len, uint16_t arp_type,
+ uint16_t port) {
+ static const uint8_t eth_bcast[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+ /* Default broadcast address for IPoIB */
+ static const uint8_t ib_bcast[] = {
+ 0x00, 0xff, 0xff, 0xff, 0xff, 0x12, 0x40, 0x1b,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0xff, 0xff, 0xff, 0xff
+ };
+ struct ether_addr eth_mac = { { 0, 0, 0, 0, 0, 0 } };
+ const uint8_t *bcast_addr = NULL;
+ uint8_t dhcp_hlen = 0;
+
+ if (arp_type == ARPHRD_ETHER) {
+ assert_return(mac_addr_len == ETH_ALEN, -EINVAL);
+ memcpy(&eth_mac, mac_addr, ETH_ALEN);
+ bcast_addr = eth_bcast;
+ dhcp_hlen = ETH_ALEN;
+ } else if (arp_type == ARPHRD_INFINIBAND) {
+ assert_return(mac_addr_len == INFINIBAND_ALEN, -EINVAL);
+ bcast_addr = ib_bcast;
+ } else
+ return -EINVAL;
+
+ return _bind_raw_socket(ifindex, link, xid, mac_addr, mac_addr_len,
+ bcast_addr, &eth_mac, arp_type, dhcp_hlen, port);
+}
+
+int dhcp_network_bind_udp_socket(int ifindex, 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;
+ char ifname[IF_NAMESIZE] = "";
+ int r;
+
+ s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
+ if (s < 0)
+ return -errno;
+
+ r = setsockopt_int(s, IPPROTO_IP, IP_TOS, IPTOS_CLASS_CS6);
+ if (r < 0)
+ return r;
+
+ r = setsockopt_int(s, SOL_SOCKET, SO_REUSEADDR, true);
+ if (r < 0)
+ return r;
+
+ if (ifindex > 0) {
+ if (if_indextoname(ifindex, ifname) == 0)
+ return -errno;
+
+ r = setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
+ if (r < 0)
+ return -errno;
+ }
+
+ if (address == INADDR_ANY) {
+ r = setsockopt_int(s, IPPROTO_IP, IP_PKTINFO, true);
+ if (r < 0)
+ return r;
+
+ r = setsockopt_int(s, SOL_SOCKET, SO_BROADCAST, true);
+ if (r < 0)
+ return r;
+
+ } else {
+ r = setsockopt_int(s, IPPROTO_IP, IP_FREEBIND, true);
+ if (r < 0)
+ return r;
+ }
+
+ r = bind(s, &src.sa, sizeof(src.in));
+ if (r < 0)
+ return -errno;
+
+ return TAKE_FD(s);
+}
+
+int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
+ const void *packet, size_t len) {
+ int r;
+
+ assert(link);
+ assert(packet);
+ assert(len);
+
+ r = sendto(s, packet, len, 0, &link->sa, SOCKADDR_LL_LEN(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) {
+ 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);
+
+ r = sendto(s, packet, len, 0, &dest.sa, sizeof(dest.in));
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 22:17:42 +0000