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-rw-r--r--src/libcharon/plugins/dhcp/dhcp_socket.c317
1 files changed, 271 insertions, 46 deletions
diff --git a/src/libcharon/plugins/dhcp/dhcp_socket.c b/src/libcharon/plugins/dhcp/dhcp_socket.c
index 6ad600f1a..24f9d4395 100644
--- a/src/libcharon/plugins/dhcp/dhcp_socket.c
+++ b/src/libcharon/plugins/dhcp/dhcp_socket.c
@@ -22,6 +22,8 @@
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/filter.h>
#include <utils/linked_list.h>
#include <utils/identification.h>
@@ -53,9 +55,14 @@ struct private_dhcp_socket_t {
rng_t *rng;
/**
- * List of active transactions
+ * List of transactions in DISCOVER
*/
- linked_list_t *active;
+ linked_list_t *discover;
+
+ /**
+ * List of transactions in REQUEST
+ */
+ linked_list_t *request;
/**
* List of successfully completed transactions
@@ -78,9 +85,14 @@ struct private_dhcp_socket_t {
int waiting;
/**
- * RAW socket
+ * DHCP send socket
+ */
+ int send;
+
+ /**
+ * DHCP receive socket
*/
- int skt;
+ int receive;
/**
* DHCP server address, or broadcast
@@ -102,10 +114,18 @@ typedef enum {
DHCP_HOST_NAME = 12,
DHCP_MESSAGE_TYPE = 53,
DHCP_PARAM_REQ_LIST = 55,
+ DHCP_OPTEND = 255,
} dhcp_option_type_t;
typedef enum {
DHCP_DISCOVER = 1,
+ DHCP_OFFER = 2,
+ DHCP_REQUEST = 3,
+ DHCP_DECLINE = 4,
+ DHCP_ACK = 5,
+ DHCP_NAK = 6,
+ DHCP_RELEASE = 7,
+ DHCP_INFORM = 8,
} dhcp_message_type_t;
typedef enum {
@@ -140,25 +160,23 @@ typedef struct __attribute__((packed)) {
} dhcp_t;
/**
- * Send DHCP discover using a given transaction
+ * Prepare a DHCP message for a given transaction
*/
-static void discover(private_dhcp_socket_t *this,
- dhcp_transaction_t *transaction)
+static int prepare_dhcp(private_dhcp_socket_t *this,
+ dhcp_transaction_t *transaction, dhcp_t *dhcp)
{
- chunk_t id_data, broadcast = chunk_from_chars(0xFF,0xFF,0xFF,0xFF);
+ chunk_t chunk, broadcast = chunk_from_chars(0xFF,0xFF,0xFF,0xFF);
identification_t *identity;
dhcp_option_t *option;
- dhcp_t dhcp;
int optlen = 0;
- u_int hash;
host_t *src;
- ssize_t len;
+ u_int hash;
- memset(&dhcp, 0, sizeof(dhcp));
- dhcp.opcode = BOOTREQUEST;
- dhcp.hw_type = ARPHRD_ETHER;
- dhcp.hw_addr_len = 6;
- dhcp.transaction_id = transaction->get_id(transaction);
+ memset(dhcp, 0, sizeof(*dhcp));
+ dhcp->opcode = BOOTREQUEST;
+ dhcp->hw_type = ARPHRD_ETHER;
+ dhcp->hw_addr_len = 6;
+ dhcp->transaction_id = transaction->get_id(transaction);
if (chunk_equals(broadcast, this->dst->get_address(this->dst)))
{
/* TODO: send with 0.0.0.0 source address */
@@ -170,36 +188,53 @@ static void discover(private_dhcp_socket_t *this,
charon->kernel_interface, this->dst, NULL);
if (src)
{
- memcpy(&dhcp.gateway_address, src->get_address(src).ptr,
- sizeof(dhcp.gateway_address));
+ memcpy(&dhcp->gateway_address, src->get_address(src).ptr,
+ sizeof(dhcp->gateway_address));
src->destroy(src);
}
}
identity = transaction->get_identity(transaction);
- id_data = identity->get_encoding(identity);
-
+ chunk = identity->get_encoding(identity);
/* magic bytes, a locally administered unicast MAC */
- dhcp.client_hw_addr[0] = 0x7A;
- dhcp.client_hw_addr[1] = 0xA7;
+ dhcp->client_hw_addr[0] = 0x7A;
+ dhcp->client_hw_addr[1] = 0xA7;
/* with ID specific postfix */
- hash = htonl(chunk_hash(id_data));
- memcpy(&dhcp.client_hw_addr[2], &hash, 4);
+ hash = htonl(chunk_hash(chunk));
+ memcpy(&dhcp->client_hw_addr[2], &hash, 4);
- dhcp.magic_cookie = htonl(0x63825363);
+ dhcp->magic_cookie = htonl(0x63825363);
- option = (dhcp_option_t*)&dhcp.options[optlen];
+ option = (dhcp_option_t*)&dhcp->options[optlen];
option->type = DHCP_MESSAGE_TYPE;
option->len = 1;
option->data[0] = DHCP_DISCOVER;
optlen += sizeof(dhcp_option_t) + option->len;
- option = (dhcp_option_t*)&dhcp.options[optlen];
+ option = (dhcp_option_t*)&dhcp->options[optlen];
option->type = DHCP_HOST_NAME;
- option->len = min(id_data.len, 64);
- memcpy(option->data, id_data.ptr, option->len);
+ option->len = min(chunk.len, 64);
+ memcpy(option->data, chunk.ptr, option->len);
optlen += sizeof(dhcp_option_t) + option->len;
+ return optlen;
+}
+
+/**
+ * Send DHCP discover using a given transaction
+ */
+static bool discover(private_dhcp_socket_t *this,
+ dhcp_transaction_t *transaction)
+{
+ dhcp_option_t *option;
+ dhcp_t dhcp;
+ ssize_t len;
+ int optlen;
+
+ optlen = prepare_dhcp(this, transaction, &dhcp);
+
+ DBG1(DBG_CFG, "sending DHCP DISCOVER to %H", this->dst);
+
option = (dhcp_option_t*)&dhcp.options[optlen];
option->type = DHCP_PARAM_REQ_LIST;
option->len = 2;
@@ -207,14 +242,25 @@ static void discover(private_dhcp_socket_t *this,
option->data[1] = DHCP_DNS_SERVER;
optlen += sizeof(dhcp_option_t) + option->len;
- dhcp.options[optlen++] = 0xFF;
+ dhcp.options[optlen++] = DHCP_OPTEND;
len = offsetof(dhcp_t, magic_cookie) + ((optlen + 4) / 64 * 64 + 64);
- if (sendto(this->skt, &dhcp, len, 0, this->dst->get_sockaddr(this->dst),
+ if (sendto(this->send, &dhcp, len, 0, this->dst->get_sockaddr(this->dst),
*this->dst->get_sockaddr_len(this->dst)) != len)
{
DBG1(DBG_CFG, "sending DHCP DISCOVER failed: %s", strerror(errno));
+ return FALSE;
}
+ return TRUE;
+}
+
+/**
+ * Send DHCP request using a given transaction
+ */
+static bool request(private_dhcp_socket_t *this,
+ dhcp_transaction_t *transaction)
+{
+ return FALSE;
}
METHOD(dhcp_socket_t, enroll, dhcp_transaction_t*,
@@ -222,15 +268,138 @@ METHOD(dhcp_socket_t, enroll, dhcp_transaction_t*,
{
dhcp_transaction_t *transaction;
u_int32_t id;
+ int tries;
this->rng->get_bytes(this->rng, sizeof(id), (u_int8_t*)&id);
transaction = dhcp_transaction_create(id, identity);
- discover(this, transaction);
- transaction->destroy(transaction);
+ this->mutex->lock(this->mutex);
+ this->discover->insert_last(this->discover, transaction);
+ tries = 3;
+ while (tries && discover(this, transaction))
+ {
+ if (!this->condvar->timed_wait(this->condvar, this->mutex, 1000))
+ {
+ break;
+ }
+ tries--;
+ }
+ if (this->discover->remove(this->discover, transaction, NULL))
+ { /* no OFFER received */
+ this->mutex->unlock(this->mutex);
+ transaction->destroy(transaction);
+ return NULL;
+ }
+
+ tries = 3;
+ while (tries && request(this, transaction))
+ {
+ if (!this->condvar->timed_wait(this->condvar, this->mutex, 1000))
+ {
+ break;
+ }
+ tries--;
+ }
+ if (this->request->remove(this->request, transaction, NULL))
+ { /* no ACK received */
+ this->mutex->unlock(this->mutex);
+ transaction->destroy(transaction);
+ return NULL;
+ }
+ this->mutex->unlock(this->mutex);
+
+ transaction->destroy(transaction);
return NULL;
}
+/**
+ * Handle a DHCP offer
+ */
+static void handle_offer(private_dhcp_socket_t *this, dhcp_t *dhcp, int optlen)
+{
+ dhcp_transaction_t *transaction;
+ enumerator_t *enumerator;
+ host_t *offer;
+
+ offer = host_create_from_chunk(AF_INET,
+ chunk_from_thing(dhcp->your_address), 0);
+ if (!offer)
+ {
+ return;
+ }
+ DBG1(DBG_CFG, "received DHCP OFFER %H", offer);
+
+ this->mutex->lock(this->mutex);
+ enumerator = this->discover->create_enumerator(this->discover);
+ while (enumerator->enumerate(enumerator, &transaction))
+ {
+ if (transaction->get_id(transaction) == dhcp->transaction_id)
+ {
+ this->discover->remove_at(this->discover, enumerator);
+ this->request->insert_last(this->request, transaction);
+ transaction->set_address(transaction, offer->clone(offer));
+ break;
+ }
+ }
+ enumerator->destroy(enumerator);
+ this->mutex->unlock(this->mutex);
+ this->condvar->broadcast(this->condvar);
+ offer->destroy(offer);
+}
+
+/**
+ * Receive DHCP responses
+ */
+static job_requeue_t receive_dhcp(private_dhcp_socket_t *this)
+{
+ struct sockaddr_ll addr;
+ socklen_t addr_len = sizeof(addr);
+ struct __attribute__((packed)) {
+ struct iphdr ip;
+ struct udphdr udp;
+ dhcp_t dhcp;
+ } packet;
+ int oldstate, optlen, origoptlen, optsize, optpos = 0;
+ ssize_t len;
+ dhcp_option_t *option;
+
+ oldstate = thread_cancelability(TRUE);
+ len = recvfrom(this->receive, &packet, sizeof(packet), 0,
+ (struct sockaddr*)&addr, &addr_len);
+ thread_cancelability(oldstate);
+
+ if (len >= sizeof(struct iphdr) + sizeof(struct udphdr) +
+ offsetof(dhcp_t, options))
+ {
+ origoptlen = optlen = len - sizeof(struct iphdr) +
+ sizeof(struct udphdr) + offsetof(dhcp_t, options);
+ while (optlen > sizeof(dhcp_option_t))
+ {
+ option = (dhcp_option_t*)&packet.dhcp.options[optpos];
+ optsize = sizeof(dhcp_option_t) + option->len;
+ if (option->type == DHCP_OPTEND || optlen < optsize)
+ {
+ break;
+ }
+ if (option->type == DHCP_MESSAGE_TYPE && option->len == 1)
+ {
+ switch (option->data[0])
+ {
+ case DHCP_OFFER:
+ handle_offer(this, &packet.dhcp, origoptlen);
+ break;
+ default:
+ break;
+ }
+ break;
+ }
+ optlen -= optsize;
+ optpos += optsize;
+ }
+ }
+ return JOB_REQUEUE_DIRECT;
+}
+
METHOD(dhcp_socket_t, destroy, void,
private_dhcp_socket_t *this)
{
@@ -242,14 +411,22 @@ METHOD(dhcp_socket_t, destroy, void,
{
this->condvar->signal(this->condvar);
}
- if (this->skt > 0)
+ if (this->send > 0)
+ {
+ close(this->send);
+ }
+ if (this->receive > 0)
{
- close(this->skt);
+ close(this->receive);
}
this->mutex->destroy(this->mutex);
this->condvar->destroy(this->condvar);
- this->active->destroy(this->active);
- this->completed->destroy(this->completed);
+ this->discover->destroy_offset(this->discover,
+ offsetof(dhcp_transaction_t, destroy));
+ this->request->destroy_offset(this->request,
+ offsetof(dhcp_transaction_t, destroy));
+ this->completed->destroy_offset(this->completed,
+ offsetof(dhcp_transaction_t, destroy));
DESTROY_IF(this->rng);
DESTROY_IF(this->dst);
free(this);
@@ -263,6 +440,36 @@ dhcp_socket_t *dhcp_socket_create()
private_dhcp_socket_t *this;
struct sockaddr_in src;
int on = 1;
+ struct sock_filter dhcp_filter_code[] = {
+ BPF_STMT(BPF_LD+BPF_B+BPF_ABS,
+ offsetof(struct iphdr, protocol)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, IPPROTO_UDP, 0, 14),
+ BPF_STMT(BPF_LD+BPF_H+BPF_ABS, sizeof(struct iphdr) +
+ offsetof(struct udphdr, source)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, DHCP_SERVER_PORT, 0, 12),
+ BPF_STMT(BPF_LD+BPF_H+BPF_ABS, sizeof(struct iphdr) +
+ offsetof(struct udphdr, dest)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, DHCP_CLIENT_PORT, 0, 10),
+ BPF_STMT(BPF_LD+BPF_B+BPF_ABS, sizeof(struct iphdr) +
+ sizeof(struct udphdr) + offsetof(dhcp_t, opcode)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, BOOTREPLY, 0, 8),
+ BPF_STMT(BPF_LD+BPF_B+BPF_ABS, sizeof(struct iphdr) +
+ sizeof(struct udphdr) + offsetof(dhcp_t, hw_type)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, ARPHRD_ETHER, 0, 6),
+ BPF_STMT(BPF_LD+BPF_B+BPF_ABS, sizeof(struct iphdr) +
+ sizeof(struct udphdr) + offsetof(dhcp_t, hw_addr_len)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 6, 0, 4),
+ BPF_STMT(BPF_LD+BPF_W+BPF_ABS, sizeof(struct iphdr) +
+ sizeof(struct udphdr) + offsetof(dhcp_t, magic_cookie)),
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0x63825363, 0, 2),
+ BPF_STMT(BPF_LD+BPF_W+BPF_LEN, 0),
+ BPF_STMT(BPF_RET+BPF_A, 0),
+ BPF_STMT(BPF_RET+BPF_K, 0),
+ };
+ struct sock_fprog dhcp_filter = {
+ sizeof(dhcp_filter_code) / sizeof(struct sock_filter),
+ dhcp_filter_code,
+ };
INIT(this,
.public = {
@@ -272,7 +479,8 @@ dhcp_socket_t *dhcp_socket_create()
.rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
.mutex = mutex_create(MUTEX_TYPE_DEFAULT),
.condvar = condvar_create(CONDVAR_TYPE_DEFAULT),
- .active = linked_list_create(),
+ .discover = linked_list_create(),
+ .request = linked_list_create(),
.completed = linked_list_create(),
);
@@ -282,7 +490,6 @@ dhcp_socket_t *dhcp_socket_create()
destroy(this);
return NULL;
}
-
this->dst = host_create_from_string(lib->settings->get_str(lib->settings,
"charon.plugins.dhcp.server", "255.255.255.255"),
DHCP_SERVER_PORT);
@@ -293,37 +500,55 @@ dhcp_socket_t *dhcp_socket_create()
return NULL;
}
- this->skt = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
- if (this->skt == -1)
+ this->send = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ if (this->send == -1)
{
DBG1(DBG_CFG, "unable to create DHCP send socket: %s", strerror(errno));
destroy(this);
return NULL;
}
-
- if (setsockopt(this->skt, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
+ if (setsockopt(this->send, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
{
DBG1(DBG_CFG, "unable to reuse DHCP socket address: %s", strerror(errno));
destroy(this);
return NULL;
}
- if (setsockopt(this->skt, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) == -1)
+ if (setsockopt(this->send, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) == -1)
{
DBG1(DBG_CFG, "unable to broadcast on DHCP socket: %s", strerror(errno));
destroy(this);
return NULL;
}
-
src.sin_family = AF_INET;
src.sin_port = htons(DHCP_CLIENT_PORT);
src.sin_addr.s_addr = INADDR_ANY;
- if (bind(this->skt, (struct sockaddr*)&src, sizeof(src)) == -1)
+ if (bind(this->send, (struct sockaddr*)&src, sizeof(src)) == -1)
{
DBG1(DBG_CFG, "unable to bind DHCP send socket: %s", strerror(errno));
destroy(this);
return NULL;
}
+ this->receive = socket(AF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
+ if (this->receive == -1)
+ {
+ DBG1(DBG_NET, "opening DHCP receive socket failed: %s", strerror(errno));
+ destroy(this);
+ return NULL;
+ }
+ if (setsockopt(this->receive, SOL_SOCKET, SO_ATTACH_FILTER,
+ &dhcp_filter, sizeof(dhcp_filter)) < 0)
+ {
+ DBG1(DBG_CFG, "installing DHCP socket filter failed: %s",
+ strerror(errno));
+ destroy(this);
+ return NULL;
+ }
+
+ this->job = callback_job_create((callback_job_cb_t)receive_dhcp,
+ this, NULL, NULL);
+ charon->processor->queue_job(charon->processor, (job_t*)this->job);
+
return &this->public;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-20 22:19:46 +0000