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path: root/src/libsystemd-network/sd-dhcp-server.c
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Diffstat (limited to 'src/libsystemd-network/sd-dhcp-server.c')
-rw-r--r--src/libsystemd-network/sd-dhcp-server.c136
1 files changed, 127 insertions, 9 deletions
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index 4c43eeb3fb..4a06833875 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -23,6 +23,8 @@
#include <sys/ioctl.h>
#include <netinet/if_ether.h>
+#include "siphash24.h"
+
#include "sd-dhcp-server.h"
#include "dhcp-server-internal.h"
#include "dhcp-internal.h"
@@ -37,6 +39,11 @@ int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, struct in_addr *addres
assert_return(size, -EINVAL);
assert_return(server->pool_start == htobe32(INADDR_ANY), -EBUSY);
assert_return(!server->pool_size, -EBUSY);
+ assert_return(!server->bound_leases, -EBUSY);
+
+ server->bound_leases = new0(DHCPLease*, size);
+ if (!server->bound_leases)
+ return -ENOMEM;
server->pool_start = address->s_addr;
server->pool_size = size;
@@ -62,13 +69,63 @@ sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) {
return server;
}
+unsigned long client_id_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+ uint64_t u;
+ const DHCPClientId *id = p;
+
+ assert(id);
+ assert(id->length);
+ assert(id->data);
+
+ siphash24((uint8_t*) &u, id->data, id->length, hash_key);
+
+ return (unsigned long) u;
+}
+
+int client_id_compare_func(const void *_a, const void *_b) {
+ const DHCPClientId *a, *b;
+
+ a = _a;
+ b = _b;
+
+ assert(!a->length || a->data);
+ assert(!b->length || b->data);
+
+ if (a->length != b->length)
+ return a->length < b->length ? -1 : 1;
+
+ return memcmp(a->data, b->data, a->length);
+}
+
+static void dhcp_lease_free(DHCPLease *lease) {
+ if (!lease)
+ return;
+
+ free(lease->client_id.data);
+ free(lease);
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPLease*, dhcp_lease_free);
+#define _cleanup_dhcp_lease_free_ _cleanup_(dhcp_lease_freep)
+
sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) {
if (server && REFCNT_DEC(server->n_ref) <= 0) {
+ DHCPLease *lease;
+ Iterator i;
+
log_dhcp_server(server, "UNREF");
sd_dhcp_server_stop(server);
sd_event_unref(server->event);
+
+ HASHMAP_FOREACH(lease, server->leases_by_client_id, i) {
+ hashmap_remove(server->leases_by_client_id, lease);
+ dhcp_lease_free(lease);
+ }
+
+ hashmap_free(server->leases_by_client_id);
+ free(server->bound_leases);
free(server);
}
@@ -90,6 +147,7 @@ int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) {
server->fd = -1;
server->address = htobe32(INADDR_ANY);
server->index = ifindex;
+ server->leases_by_client_id = hashmap_new(client_id_hash_func, client_id_compare_func);
*ret = server;
server = NULL;
@@ -478,9 +536,24 @@ static int ensure_sane_request(DHCPRequest *req, DHCPMessage *message) {
return 0;
}
+static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) {
+ assert(server);
+
+ if (!server->pool_size)
+ return -EINVAL;
+
+ if (be32toh(requested_ip) < be32toh(server->pool_start) ||
+ be32toh(requested_ip) >= be32toh(server->pool_start) +
+ + server->pool_size)
+ return -EINVAL;
+
+ return be32toh(requested_ip) - be32toh(server->pool_start);
+}
+
int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
size_t length) {
_cleanup_dhcp_request_free_ DHCPRequest *req = NULL;
+ DHCPLease *existing_lease;
int type, r;
assert(server);
@@ -504,10 +577,13 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
/* this only fails on critical errors */
return r;
+ existing_lease = hashmap_get(server->leases_by_client_id, &req->client_id);
+
switch(type) {
case DHCP_DISCOVER:
{
- be32_t address;
+ be32_t address = INADDR_ANY;
+ unsigned i;
log_dhcp_server(server, "DISCOVER (0x%x)",
be32toh(req->message->xid));
@@ -516,9 +592,22 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
/* no pool allocated */
return 0;
- /* for now pick a random address from the pool */
- address = htobe32(be32toh(server->pool_start) +
- (random_u32() % server->pool_size));
+ /* for now pick a random free address from the pool */
+ if (existing_lease)
+ address = existing_lease->address;
+ else {
+ for (i = 0; i < server->pool_size; i++) {
+ if (!server->bound_leases[server->next_offer]) {
+ address = htobe32(be32toh(server->pool_start) + server->next_offer);
+ break;
+ } else
+ server->next_offer = (server->next_offer + 1) % server->pool_size;
+ }
+ }
+
+ if (address == INADDR_ANY)
+ /* no free addresses left */
+ return 0;
r = server_send_offer(server, req, address);
if (r < 0) {
@@ -538,6 +627,7 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
{
be32_t address;
bool init_reboot = false;
+ int pool_offset;
/* see RFC 2131, section 4.3.2 */
@@ -584,20 +674,48 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
address = req->message->ciaddr;
}
- /* for now we just verify that the address is from the pool, not
- whether or not it is taken */
- if (htobe32(req->requested_ip) >= htobe32(server->pool_start) &&
- htobe32(req->requested_ip) < htobe32(server->pool_start) +
- + server->pool_size) {
+ pool_offset = get_pool_offset(server, address);
+
+ /* verify that the requested address is from the pool, and either
+ owned by the current client or free */
+ if (pool_offset >= 0 &&
+ server->bound_leases[pool_offset] == existing_lease) {
+ DHCPLease *lease;
+ usec_t time_now;
+
+ if (!existing_lease) {
+ lease = new0(DHCPLease, 1);
+ lease->address = req->requested_ip;
+ lease->client_id.data = memdup(req->client_id.data,
+ req->client_id.length);
+ if (!lease->client_id.data)
+ return -ENOMEM;
+ lease->client_id.length = req->client_id.length;
+ } else
+ lease = existing_lease;
+
+ r = sd_event_now(server->event, CLOCK_MONOTONIC, &time_now);
+ if (r < 0)
+ time_now = now(CLOCK_MONOTONIC);
+ lease->expiration = req->lifetime * USEC_PER_SEC + time_now;
+
r = server_send_ack(server, req, address);
if (r < 0) {
/* this only fails on critical errors */
log_dhcp_server(server, "could not send ack: %s",
strerror(-r));
+
+ if (!existing_lease)
+ dhcp_lease_free(lease);
+
return r;
} else {
log_dhcp_server(server, "ACK (0x%x)",
be32toh(req->message->xid));
+
+ server->bound_leases[pool_offset] = lease;
+ hashmap_put(server->leases_by_client_id, &lease->client_id, lease);
+
return DHCP_ACK;
}
} else if (init_reboot) {
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-14 13:35:18 +0000