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-rw-r--r--src/libsystemd-dhcp/dhcp-internal.h9
-rw-r--r--src/libsystemd-dhcp/dhcp-packet.c171
-rw-r--r--src/libsystemd-dhcp/sd-dhcp-client.c159
3 files changed, 216 insertions, 123 deletions
diff --git a/src/libsystemd-dhcp/dhcp-internal.h b/src/libsystemd-dhcp/dhcp-internal.h
index 43b5b1d000..3f1e000365 100644
--- a/src/libsystemd-dhcp/dhcp-internal.h
+++ b/src/libsystemd-dhcp/dhcp-internal.h
@@ -6,6 +6,7 @@
This file is part of systemd.
Copyright (C) 2013 Intel Corporation. All rights reserved.
+ Copyright (C) 2014 Tom Gundersen
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
@@ -40,5 +41,13 @@ int dhcp_option_append(uint8_t **buf, size_t *buflen, uint8_t code,
typedef int (*dhcp_option_cb_t)(uint8_t code, uint8_t len,
const uint8_t *option, void *user_data);
+
int dhcp_option_parse(DHCPMessage *message, size_t len,
dhcp_option_cb_t cb, void *user_data);
+
+int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid, uint8_t type,
+ uint16_t secs, uint8_t **opt, size_t *optlen);
+
+void dhcp_packet_append_ip_headers(DHCPPacket *packet, uint8_t op, uint16_t len);
+
+int dhcp_packet_verify_headers(DHCPPacket *packet, uint8_t op, size_t len);
diff --git a/src/libsystemd-dhcp/dhcp-packet.c b/src/libsystemd-dhcp/dhcp-packet.c
new file mode 100644
index 0000000000..d606d55a05
--- /dev/null
+++ b/src/libsystemd-dhcp/dhcp-packet.c
@@ -0,0 +1,171 @@
+/***
+ This file is part of systemd.
+
+ Copyright (C) 2013 Intel Corporation. All rights reserved.
+ Copyright (C) 2014 Tom Gundersen
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <net/ethernet.h>
+#include <net/if_arp.h>
+#include <sys/param.h>
+
+#include "util.h"
+#include "list.h"
+
+#include "dhcp-protocol.h"
+#include "dhcp-lease.h"
+#include "dhcp-internal.h"
+#include "sd-dhcp-client.h"
+
+#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
+
+int dhcp_message_init(DHCPMessage *message, uint8_t op, uint32_t xid,
+ uint8_t type, uint16_t secs, uint8_t **opt,
+ size_t *optlen) {
+ int err;
+
+ *opt = (uint8_t *)(message + 1);
+
+ if (*optlen < 4)
+ return -ENOBUFS;
+ *optlen -= 4;
+
+ message->op = op;
+ message->htype = ARPHRD_ETHER;
+ message->hlen = ETHER_ADDR_LEN;
+ message->xid = htobe32(xid);
+
+ /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
+ refuse to issue an DHCP lease if 'secs' is set to zero */
+ message->secs = htobe16(secs);
+
+ (*opt)[0] = 0x63;
+ (*opt)[1] = 0x82;
+ (*opt)[2] = 0x53;
+ (*opt)[3] = 0x63;
+
+ *opt += 4;
+
+ err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
+ &type);
+ if (err < 0)
+ return err;
+
+ return 0;
+}
+
+static uint16_t dhcp_checksum(void *buf, int len) {
+ uint32_t sum;
+ uint16_t *check;
+ int i;
+ uint8_t *odd;
+
+ sum = 0;
+ check = buf;
+
+ for (i = 0; i < len / 2 ; i++)
+ sum += check[i];
+
+ if (len & 0x01) {
+ odd = buf;
+ sum += odd[len - 1];
+ }
+
+ while (sum >> 16)
+ sum = (sum & 0xffff) + (sum >> 16);
+
+ return ~sum;
+}
+
+void dhcp_packet_append_ip_headers(DHCPPacket *packet, uint8_t op,
+ uint16_t len) {
+ assert(op == BOOTREQUEST || op == BOOTREPLY);
+
+ packet->ip.version = IPVERSION;
+ packet->ip.ihl = DHCP_IP_SIZE / 4;
+ packet->ip.tot_len = htobe16(len);
+
+ packet->ip.protocol = IPPROTO_UDP;
+ packet->ip.saddr = INADDR_ANY;
+ packet->ip.daddr = INADDR_BROADCAST;
+
+ switch (op) {
+ case BOOTREQUEST:
+ packet->udp.source = htobe16(DHCP_PORT_CLIENT);
+ packet->udp.dest = htobe16(DHCP_PORT_SERVER);
+ break;
+ case BOOTREPLY:
+ packet->udp.source = htobe16(DHCP_PORT_SERVER);
+ packet->udp.dest = htobe16(DHCP_PORT_CLIENT);
+ break;
+ }
+
+ packet->udp.len = htobe16(len - DHCP_IP_SIZE);
+
+ packet->ip.check = packet->udp.len;
+ packet->udp.check = dhcp_checksum(&packet->ip.ttl, len - 8);
+
+ packet->ip.ttl = IPDEFTTL;
+ packet->ip.check = 0;
+ packet->ip.check = dhcp_checksum(&packet->ip, DHCP_IP_SIZE);
+}
+
+int dhcp_packet_verify_headers(DHCPPacket *packet, uint8_t op, size_t len) {
+ size_t hdrlen;
+
+ assert(op == BOOTREQUEST || op == BOOTREPLY);
+
+ if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
+ return -EINVAL;
+
+ hdrlen = packet->ip.ihl * 4;
+ if (hdrlen < 20 || hdrlen > len || dhcp_checksum(&packet->ip, hdrlen))
+ return -EINVAL;
+
+ if (hdrlen + be16toh(packet->udp.len) > len)
+ return -EINVAL;
+
+ if (packet->udp.check) {
+ packet->ip.check = packet->udp.len;
+ packet->ip.ttl = 0;
+
+ if (dhcp_checksum(&packet->ip.ttl,
+ be16toh(packet->udp.len) + 12))
+ return -EINVAL;
+ }
+
+ if (packet->dhcp.op != op)
+ return -EINVAL;
+
+ switch (op) {
+ case BOOTREQUEST:
+ if (be16toh(packet->udp.source) != DHCP_PORT_CLIENT ||
+ be16toh(packet->udp.dest) != DHCP_PORT_SERVER)
+ return -EINVAL;
+ break;
+ case BOOTREPLY:
+ if (be16toh(packet->udp.source) != DHCP_PORT_SERVER ||
+ be16toh(packet->udp.dest) != DHCP_PORT_CLIENT)
+ return -EINVAL;
+ break;
+ }
+
+ return 0;
+}
diff --git a/src/libsystemd-dhcp/sd-dhcp-client.c b/src/libsystemd-dhcp/sd-dhcp-client.c
index 72998bc6cb..4f41b4c06a 100644
--- a/src/libsystemd-dhcp/sd-dhcp-client.c
+++ b/src/libsystemd-dhcp/sd-dhcp-client.c
@@ -198,118 +198,54 @@ static int client_stop(sd_dhcp_client *client, int error) {
return 0;
}
-static int client_packet_init(sd_dhcp_client *client, uint8_t type,
- DHCPMessage *message, uint16_t secs,
- uint8_t **opt, size_t *optlen) {
- int err;
- be16_t max_size;
-
- *opt = (uint8_t *)(message + 1);
-
- if (*optlen < 4)
- return -ENOBUFS;
- *optlen -= 4;
+static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
+ uint8_t type, uint16_t secs, uint8_t **opt,
+ size_t *optlen) {
+ int r;
- message->op = BOOTREQUEST;
- message->htype = 1;
- message->hlen = ETHER_ADDR_LEN;
- message->xid = htobe32(client->xid);
+ r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
+ secs, opt, optlen);
+ if (r < 0)
+ return r;
- /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
- refuse to issue an DHCP lease if 'secs' is set to zero */
- message->secs = htobe16(secs);
+ memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
if (client->state == DHCP_STATE_RENEWING ||
client->state == DHCP_STATE_REBINDING)
message->ciaddr = client->lease->address;
- memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
- (*opt)[0] = 0x63;
- (*opt)[1] = 0x82;
- (*opt)[2] = 0x53;
- (*opt)[3] = 0x63;
-
- *opt += 4;
-
- err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
- &type);
- if (err < 0)
- return err;
-
/* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
Identifier option is not set */
- err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
- ETH_ALEN, &client->mac_addr);
- if (err < 0)
- return err;
+ r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
+ ETH_ALEN, &client->mac_addr);
+ if (r < 0)
+ return r;
if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
- err = dhcp_option_append(opt, optlen,
- DHCP_OPTION_PARAMETER_REQUEST_LIST,
- client->req_opts_size,
- client->req_opts);
- if (err < 0)
- return err;
+ be16_t max_size;
+
+ r = dhcp_option_append(opt, optlen,
+ DHCP_OPTION_PARAMETER_REQUEST_LIST,
+ client->req_opts_size,
+ client->req_opts);
+ if (r < 0)
+ return r;
/* Some DHCP servers will send bigger DHCP packets than the
defined default size unless the Maximum Messge Size option
is explicitely set */
max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
DHCP_CLIENT_MIN_OPTIONS_SIZE);
- err = dhcp_option_append(opt, optlen,
- DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
- 2, &max_size);
- if (err < 0)
- return err;
+ r = dhcp_option_append(opt, optlen,
+ DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
+ 2, &max_size);
+ if (r < 0)
+ return r;
}
return 0;
}
-static uint16_t client_checksum(void *buf, int len) {
- uint32_t sum;
- uint16_t *check;
- int i;
- uint8_t *odd;
-
- sum = 0;
- check = buf;
-
- for (i = 0; i < len / 2 ; i++)
- sum += check[i];
-
- if (len & 0x01) {
- odd = buf;
- sum += odd[len - 1];
- }
-
- while (sum >> 16)
- sum = (sum & 0xffff) + (sum >> 16);
-
- return ~sum;
-}
-
-static void client_append_ip_headers(DHCPPacket *packet, uint16_t len) {
- packet->ip.version = IPVERSION;
- packet->ip.ihl = DHCP_IP_SIZE / 4;
- packet->ip.tot_len = htobe16(len);
-
- packet->ip.protocol = IPPROTO_UDP;
- packet->ip.saddr = INADDR_ANY;
- packet->ip.daddr = INADDR_BROADCAST;
-
- packet->udp.source = htobe16(DHCP_PORT_CLIENT);
- packet->udp.dest = htobe16(DHCP_PORT_SERVER);
- packet->udp.len = htobe16(len - DHCP_IP_SIZE);
-
- packet->ip.check = packet->udp.len;
- packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
-
- packet->ip.ttl = IPDEFTTL;
- packet->ip.check = 0;
- packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
-}
-
static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
int err = 0;
_cleanup_free_ DHCPPacket *discover;
@@ -324,8 +260,8 @@ static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
if (!discover)
return -ENOMEM;
- err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
- secs, &opt, &optlen);
+ err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
+ secs, &opt, &optlen);
if (err < 0)
return err;
@@ -341,7 +277,7 @@ static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
if (err < 0)
return err;
- client_append_ip_headers(discover, len);
+ dhcp_packet_append_ip_headers(discover, BOOTREQUEST, len);
err = dhcp_network_send_raw_socket(client->fd, &client->link,
discover, len);
@@ -362,8 +298,8 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
if (!request)
return -ENOMEM;
- err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
- &opt, &optlen);
+ err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
+ &opt, &optlen);
if (err < 0)
return err;
@@ -391,7 +327,7 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
&request->dhcp,
len - DHCP_IP_UDP_SIZE);
} else {
- client_append_ip_headers(request, len);
+ dhcp_packet_append_ip_headers(request, BOOTREQUEST, len);
err = dhcp_network_send_raw_socket(client->fd, &client->link,
request, len);
@@ -606,34 +542,11 @@ static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
size_t len) {
- size_t hdrlen;
-
- if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
- return -EINVAL;
-
- hdrlen = message->ip.ihl * 4;
- if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
- hdrlen))
- return -EINVAL;
-
- if (hdrlen + be16toh(message->udp.len) > len)
- return -EINVAL;
-
- if (message->udp.check) {
- message->ip.check = message->udp.len;
- message->ip.ttl = 0;
-
- if (client_checksum(&message->ip.ttl,
- be16toh(message->udp.len) + 12))
- return -EINVAL;
- }
-
- if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
- be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
- return -EINVAL;
+ int r;
- if (message->dhcp.op != BOOTREPLY)
- return -EINVAL;
+ r = dhcp_packet_verify_headers(message, BOOTREPLY, len);
+ if (r < 0)
+ return r;
if (be32toh(message->dhcp.xid) != client->xid)
return -EINVAL;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-10 17:16:23 +0000