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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, 131 insertions, 5 deletions
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index 07715c5e9a..e170cfabf1 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -29,6 +29,21 @@
#define DHCP_DEFAULT_LEASE_TIME 60
+int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, struct in_addr *address,
+ size_t size) {
+ assert_return(server, -EINVAL);
+ assert_return(address, -EINVAL);
+ assert_return(address->s_addr, -EINVAL);
+ assert_return(size, -EINVAL);
+ assert_return(server->pool_start == htobe32(INADDR_ANY), -EBUSY);
+ assert_return(!server->pool_size, -EBUSY);
+
+ server->pool_start = address->s_addr;
+ server->pool_size = size;
+
+ return 0;
+}
+
int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address) {
assert_return(server, -EINVAL);
assert_return(address, -EINVAL);
@@ -288,7 +303,7 @@ static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret,
assert(server);
assert(ret);
assert(_optoffset);
- assert(type == DHCP_OFFER);
+ assert(IN_SET(type, DHCP_OFFER, DHCP_ACK));
packet = malloc0(sizeof(DHCPPacket) + req->max_optlen);
if (!packet)
@@ -310,7 +325,7 @@ static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret,
return 0;
}
-static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req) {
+static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req, be32_t address) {
_cleanup_free_ DHCPPacket *packet = NULL;
size_t offset;
be32_t lease_time;
@@ -320,8 +335,7 @@ static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req) {
if (r < 0)
return r;
- /* for now offer a random IP */
- packet->dhcp.yiaddr = random_u32();
+ packet->dhcp.yiaddr = address;
/* for one minute */
lease_time = htobe32(DHCP_DEFAULT_LEASE_TIME);
@@ -337,6 +351,32 @@ static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req) {
return 0;
}
+static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req, be32_t address) {
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ size_t offset;
+ be32_t lease_time;
+ int r;
+
+ r = server_message_init(server, &packet, DHCP_ACK, &offset, req);
+ if (r < 0)
+ return r;
+
+ packet->dhcp.yiaddr = address;
+
+ /* for ten seconds */
+ lease_time = htobe32(DHCP_DEFAULT_LEASE_TIME);
+ r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0,
+ DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, &lease_time);
+ if (r < 0)
+ return r;
+
+ r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
static int parse_request(uint8_t code, uint8_t len, const uint8_t *option,
void *user_data) {
DHCPRequest *req = user_data;
@@ -344,6 +384,11 @@ static int parse_request(uint8_t code, uint8_t len, const uint8_t *option,
assert(req);
switch(code) {
+ case DHCP_OPTION_REQUESTED_IP_ADDRESS:
+ if (len == 4)
+ req->requested_ip = *(be32_t*)option;
+
+ break;
case DHCP_OPTION_SERVER_IDENTIFIER:
if (len == 4)
req->server_id = *(be32_t*)option;
@@ -439,10 +484,21 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
switch(type) {
case DHCP_DISCOVER:
+ {
+ be32_t address;
+
log_dhcp_server(server, "DISCOVER (0x%x)",
be32toh(req->message->xid));
- r = server_send_offer(server, req);
+ if (!server->pool_size)
+ /* 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));
+
+ r = server_send_offer(server, req, address);
if (r < 0) {
/* this only fails on critical errors */
log_dhcp_server(server, "could not send offer: %s",
@@ -456,6 +512,76 @@ int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message,
break;
}
+ case DHCP_REQUEST:
+ {
+ be32_t address;
+
+ /* see RFC 2131, section 4.3.2 */
+
+ if (req->server_id) {
+ log_dhcp_server(server, "REQUEST (selecting) (0x%x)",
+ be32toh(req->message->xid));
+
+ /* SELECTING */
+ if (req->server_id != server->address)
+ /* client did not pick us */
+ return 0;
+
+ if (req->message->ciaddr)
+ /* this MUST be zero */
+ return 0;
+
+ if (!req->requested_ip)
+ /* this must be filled in with the yiaddr
+ from the chosen OFFER */
+ return 0;
+
+ address = req->requested_ip;
+ } else if (req->requested_ip) {
+ log_dhcp_server(server, "REQUEST (init-reboot) (0x%x)",
+ be32toh(req->message->xid));
+
+ /* INIT-REBOOT */
+ if (req->message->ciaddr)
+ /* this MUST be zero */
+ return 0;
+
+ /* TODO: check if requested IP is correct, NAK if not */
+ address = req->requested_ip;
+ } else {
+ log_dhcp_server(server, "REQUEST (rebinding/renewing) (0x%x)",
+ be32toh(req->message->xid));
+
+ /* REBINDING / RENEWING */
+ if (!req->message->ciaddr)
+ /* this MUST be filled in with clients IP address */
+ return 0;
+
+ 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) {
+ 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));
+ return r;
+ } else {
+ log_dhcp_server(server, "ACK (0x%x)",
+ be32toh(req->message->xid));
+ return DHCP_ACK;
+ }
+ } else
+ return 0;
+
+ break;
+ }
+ }
return 0;
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-05 08:43:20 +0000