[systemd-devel] [PATCH 11/17] sd-dhcp-server: add basic REQUEST/ACK support
Zbigniew Jędrzejewski-Szmek
zbyszek at in.waw.pl
Tue May 27 08:48:18 PDT 2014
On Mon, May 26, 2014 at 09:39:40PM +0200, Tom Gundersen wrote:
> ---
> src/libsystemd-network/dhcp-server-internal.h | 3 +
> src/libsystemd-network/sd-dhcp-server.c | 135 +++++++++++++++++++++++++-
> src/libsystemd-network/test-dhcp-server.c | 37 +++++++
> src/systemd/sd-dhcp-server.h | 1 +
> 4 files changed, 171 insertions(+), 5 deletions(-)
>
> diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
> index 381304e..cd480e7 100644
> --- a/src/libsystemd-network/dhcp-server-internal.h
> +++ b/src/libsystemd-network/dhcp-server-internal.h
> @@ -40,6 +40,8 @@ struct sd_dhcp_server {
>
> int index;
> be32_t address;
> + be32_t pool_start;
> + size_t pool_size;
> };
>
> typedef struct DHCPClientId {
> @@ -55,6 +57,7 @@ typedef struct DHCPRequest {
> DHCPClientId client_id;
> size_t max_optlen;
> be32_t server_id;
> + be32_t requested_ip;
> } DHCPRequest;
>
> DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_server*, sd_dhcp_server_unref);
> diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
> index be6938b..01cd8be 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 ten seconds */
> 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) {
> log_dhcp_server(server, "could not send offer: %s",
> strerror(-r));
> @@ -455,6 +511,75 @@ 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) {
> + log_dhcp_server(server, "could not send ack: %s",
> + strerror(-r));
> + return 0;
> + } else {
> + log_dhcp_server(server, "ACK (0x%x)",
> + be32toh(req->message->xid));
> + return DHCP_ACK;
> + }
> + } else
> + return 0;
> +
> + break;
> + }
> + }
Should this closing brace be here? (hard to see in the diff format)
> return 0;
> }
> diff --git a/src/libsystemd-network/test-dhcp-server.c b/src/libsystemd-network/test-dhcp-server.c
> index ed3aaf9..7255a69 100644
> --- a/src/libsystemd-network/test-dhcp-server.c
> +++ b/src/libsystemd-network/test-dhcp-server.c
> @@ -59,6 +59,11 @@ static void test_basic(sd_event *event) {
> assert_se(sd_dhcp_server_set_address(server, &address_lo) >= 0);
> assert_se(sd_dhcp_server_set_address(server, &address_lo) == -EBUSY);
>
> + assert_se(sd_dhcp_server_set_lease_pool(server, &address_any, 1) == -EINVAL);
> + assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 0) == -EINVAL);
> + assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 1) >= 0);
> + assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 1) == -EBUSY);
> +
> assert_se(sd_dhcp_server_start(server) >= 0);
> assert_se(sd_dhcp_server_start(server) == -EBUSY);
> assert_se(sd_dhcp_server_stop(server) >= 0);
> @@ -75,11 +80,23 @@ static void test_message_handler(void) {
> uint8_t length;
> uint8_t type;
> } _packed_ option_type;
> + struct {
> + uint8_t code;
> + uint8_t length;
> + be32_t address;
> + } _packed_ option_requested_ip;
> + struct {
> + uint8_t code;
> + uint8_t length;
> + be32_t address;
> + } _packed_ option_server_id;
> uint8_t end;
> } _packed_ test = {
> .message.op = BOOTREQUEST,
> .message.htype = ARPHRD_ETHER,
> .message.hlen = ETHER_ADDR_LEN,
> + .message.xid = htobe32(0x12345678),
> + .message.chaddr = { 'A', 'B', 'C', 'D', 'E', 'F' },
> .option_type.code = DHCP_OPTION_MESSAGE_TYPE,
> .option_type.length = 1,
> .option_type.type = DHCP_DISCOVER,
> @@ -94,6 +111,8 @@ static void test_message_handler(void) {
> assert_se(sd_dhcp_server_attach_event(server, NULL, 0) >= 0);
> assert_se(sd_dhcp_server_start(server) >= 0);
>
> + assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
> + assert_se(sd_dhcp_server_set_lease_pool(server, &address_lo, 10) >= 0);
> assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
>
> test.end = 0;
> @@ -125,6 +144,24 @@ static void test_message_handler(void) {
> assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
> test.message.hlen = ETHER_ADDR_LEN;
> assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_OFFER);
> +
> + test.option_type.type = DHCP_REQUEST;
> + assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
> + test.option_requested_ip.code = DHCP_OPTION_REQUESTED_IP_ADDRESS;
> + test.option_requested_ip.length = 4;
> + test.option_requested_ip.address = htobe32(0x12345678);
> + assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
> + test.option_server_id.code = DHCP_OPTION_SERVER_IDENTIFIER;
> + test.option_server_id.length = 4;
> + test.option_server_id.address = htobe32(INADDR_LOOPBACK);
> + test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 3);
> + assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == DHCP_ACK);
> + test.option_server_id.address = htobe32(0x12345678);
> + test.option_requested_ip.address = htobe32(INADDR_LOOPBACK + 3);
> + assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
> + test.option_server_id.address = htobe32(INADDR_LOOPBACK + 3);
> + test.option_requested_ip.address = htobe32(0x12345678);
> + assert_se(dhcp_server_handle_message(server, (DHCPMessage*)&test, sizeof(test)) == 0);
> }
>
> int main(int argc, char *argv[]) {
> diff --git a/src/systemd/sd-dhcp-server.h b/src/systemd/sd-dhcp-server.h
> index 5edeffc..cd0ff72 100644
> --- a/src/systemd/sd-dhcp-server.h
> +++ b/src/systemd/sd-dhcp-server.h
> @@ -42,4 +42,5 @@ int sd_dhcp_server_start(sd_dhcp_server *server);
> int sd_dhcp_server_stop(sd_dhcp_server *server);
>
> int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address);
> +int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, struct in_addr *start, size_t size);
> #endif
Zbyszek
More information about the systemd-devel
mailing list