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https://github.com/systemd/systemd.git
synced 2024-12-14 20:54:02 +08:00
sd-dhcp-client: explicitly handle raw and udp messages
Split the recevie_message callback into _raw and _udp parts and a generic DHCPMessage handler. Also always verify the xid/MAC, rather than only for udp messages.
This commit is contained in:
Tom Gundersen
parent
ee3a6a51e5
commit
e500270271
@ -70,8 +70,10 @@ static const uint8_t default_req_opts[] = {
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DHCP_OPTION_NTP_SERVER,
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};
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static int client_receive_message(sd_event_source *s, int fd,
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uint32_t revents, void *userdata);
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static int client_receive_message_raw(sd_event_source *s, int fd,
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uint32_t revents, void *userdata);
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static int client_receive_message_udp(sd_event_source *s, int fd,
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uint32_t revents, void *userdata);
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int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
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void *userdata) {
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@ -357,7 +359,7 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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switch (client->state) {
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case DHCP_STATE_RENEWING:
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time_left = (client->lease->t2 - client->lease->t1)/2;
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time_left = (client->lease->t2 - client->lease->t1) / 2;
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if (time_left < 60)
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time_left = 60;
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@ -367,7 +369,7 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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case DHCP_STATE_REBINDING:
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time_left = (client->lease->lifetime - client->lease->t2)/2;
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time_left = (client->lease->lifetime - client->lease->t2) / 2;
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if (time_left < 60)
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time_left = 60;
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@ -398,7 +400,8 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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if (r < 0)
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goto error;
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r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
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r = sd_event_source_set_priority(client->timeout_resend,
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client->event_priority);
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if (r < 0)
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goto error;
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@ -455,19 +458,21 @@ error:
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return 0;
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}
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static int client_initialize_events(sd_dhcp_client *client, usec_t usec) {
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static int client_initialize_events(sd_dhcp_client *client,
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sd_event_io_handler_t io_callback,
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usec_t usec) {
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int r;
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assert(client);
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assert(client->event);
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r = sd_event_add_io(client->event, client->fd, EPOLLIN,
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client_receive_message, client,
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&client->receive_message);
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r = sd_event_add_io(client->event, client->fd, EPOLLIN, io_callback,
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client, &client->receive_message);
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if (r < 0)
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goto error;
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r = sd_event_source_set_priority(client->receive_message, client->event_priority);
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r = sd_event_source_set_priority(client->receive_message,
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client->event_priority);
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if (r < 0)
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goto error;
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@ -477,7 +482,8 @@ static int client_initialize_events(sd_dhcp_client *client, usec_t usec) {
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if (r < 0)
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goto error;
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r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
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r = sd_event_source_set_priority(client->timeout_resend,
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client->event_priority);
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error:
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if (r < 0)
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@ -518,10 +524,12 @@ static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
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client->fd = r;
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return client_initialize_events(client, usec);
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return client_initialize_events(client, client_receive_message_raw,
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usec);
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}
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static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
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static int client_timeout_t1(sd_event_source *s, uint64_t usec,
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void *userdata) {
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sd_dhcp_client *client = userdata;
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int r;
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@ -537,47 +545,23 @@ static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
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client->fd = r;
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return client_initialize_events(client, usec);
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return client_initialize_events(client, client_receive_message_udp, usec);
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}
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static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
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size_t len) {
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int r;
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r = dhcp_packet_verify_headers(message, BOOTREPLY, len);
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if (r < 0)
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return r;
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if (be32toh(message->dhcp.xid) != client->xid)
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return -EINVAL;
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if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
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ETHER_ADDR_LEN))
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return -EINVAL;
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return 0;
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}
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static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
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size_t len) {
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static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
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size_t len) {
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_cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
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int r;
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r = client_verify_headers(client, offer, len);
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if (r < 0)
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return r;
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r = dhcp_lease_new(&lease);
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if (r < 0)
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return r;
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len = len - DHCP_IP_UDP_SIZE;
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r = dhcp_option_parse(&offer->dhcp, len, dhcp_lease_parse_options,
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lease);
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r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
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if (r != DHCP_OFFER)
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return -ENOMSG;
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lease->address = offer->dhcp.yiaddr;
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lease->address = offer->yiaddr;
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if (lease->address == INADDR_ANY ||
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lease->server_address == INADDR_ANY ||
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@ -591,38 +575,23 @@ static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
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return 0;
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}
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static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
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size_t len) {
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DHCPPacket *ack;
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DHCPMessage *dhcp;
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static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
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size_t len) {
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_cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
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int r;
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if (client->state == DHCP_STATE_RENEWING) {
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dhcp = (DHCPMessage *)buf;
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} else {
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ack = (DHCPPacket *)buf;
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r = client_verify_headers(client, ack, len);
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if (r < 0)
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return r;
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dhcp = &ack->dhcp;
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len -= DHCP_IP_UDP_SIZE;
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}
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r = dhcp_lease_new(&lease);
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if (r < 0)
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return r;
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r = dhcp_option_parse(dhcp, len, dhcp_lease_parse_options, lease);
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r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
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if (r == DHCP_NAK)
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return DHCP_EVENT_NO_LEASE;
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if (r != DHCP_ACK)
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return -ENOMSG;
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lease->address = dhcp->yiaddr;
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lease->address = ack->yiaddr;
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if (lease->address == INADDR_ANY ||
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lease->server_address == INADDR_ANY ||
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@ -681,7 +650,8 @@ static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
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if (r < 0)
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return r;
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r = sd_event_source_set_priority(client->timeout_t1, client->event_priority);
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r = sd_event_source_set_priority(client->timeout_t1,
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client->event_priority);
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if (r < 0)
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return r;
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@ -706,7 +676,8 @@ static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
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if (r < 0)
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return r;
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r = sd_event_source_set_priority(client->timeout_t2, client->event_priority);
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r = sd_event_source_set_priority(client->timeout_t2,
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client->event_priority);
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if (r < 0)
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return r;
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@ -722,40 +693,34 @@ static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
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if (r < 0)
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return r;
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r = sd_event_source_set_priority(client->timeout_expire, client->event_priority);
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r = sd_event_source_set_priority(client->timeout_expire,
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client->event_priority);
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if (r < 0)
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return r;
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return 0;
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}
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static int client_receive_message(sd_event_source *s, int fd,
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uint32_t revents, void *userdata) {
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sd_dhcp_client *client = userdata;
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uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
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int buflen = sizeof(buf);
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int len, r = 0, notify_event = 0;
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DHCPPacket *message;
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usec_t time_now;
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static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
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int len, usec_t time_now) {
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int r = 0, notify_event = 0;
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assert(s);
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assert(client);
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assert(client->event);
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assert(message);
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len = read(fd, &buf, buflen);
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if (len < 0)
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return 0;
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if (be32toh(message->xid) != client->xid)
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return -EINVAL;
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r = sd_event_get_now_monotonic(client->event, &time_now);
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if (r < 0)
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goto error;
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if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
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ETHER_ADDR_LEN))
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return -EINVAL;
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switch (client->state) {
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case DHCP_STATE_SELECTING:
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message = (DHCPPacket *)&buf;
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if (client_receive_offer(client, message, len) >= 0) {
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r = client_handle_offer(client, message, len);
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if (r >= 0) {
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client->timeout_resend =
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sd_event_source_unref(client->timeout_resend);
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@ -770,7 +735,8 @@ static int client_receive_message(sd_event_source *s, int fd,
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if (r < 0)
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goto error;
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r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
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r = sd_event_source_set_priority(client->timeout_resend,
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client->event_priority);
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if (r < 0)
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goto error;
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}
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@ -781,7 +747,7 @@ static int client_receive_message(sd_event_source *s, int fd,
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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r = client_receive_ack(client, buf, len);
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r = client_handle_ack(client, message, len);
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if (r == DHCP_EVENT_NO_LEASE)
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goto error;
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@ -832,6 +798,62 @@ error:
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return 0;
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}
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static int client_receive_message_raw(sd_event_source *s, int fd,
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uint32_t revents, void *userdata) {
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sd_dhcp_client *client = userdata;
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uint8_t buf[sizeof(DHCPMessage) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
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int buflen = sizeof(buf);
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int len, r = 0;
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usec_t time_now;
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assert(s);
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assert(client);
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assert(client->event);
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len = read(fd, &buf, buflen);
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if (len < 0)
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return 0;
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r = sd_event_get_now_monotonic(client->event, &time_now);
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if (r < 0)
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return client_stop(client, r);
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return client_handle_message(client, (DHCPMessage *) buf, len,
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time_now);
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}
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static int client_receive_message_udp(sd_event_source *s, int fd,
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uint32_t revents, void *userdata) {
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sd_dhcp_client *client = userdata;
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uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
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int buflen = sizeof(buf);
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int len, r = 0;
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DHCPPacket *packet;
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usec_t time_now;
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assert(s);
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assert(client);
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assert(client->event);
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len = read(fd, &buf, buflen);
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if (len < 0)
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return 0;
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packet = (DHCPPacket *) buf;
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r = dhcp_packet_verify_headers(packet, BOOTREPLY, len);
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if (r < 0)
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return r;
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len -= DHCP_IP_UDP_SIZE;
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r = sd_event_get_now_monotonic(client->event, &time_now);
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if (r < 0)
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return client_stop(client, r);
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return client_handle_message(client, &packet->dhcp, len, time_now);
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}
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int sd_dhcp_client_start(sd_dhcp_client *client) {
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int r;
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@ -854,14 +876,16 @@ int sd_dhcp_client_start(sd_dhcp_client *client) {
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client->start_time = now(CLOCK_MONOTONIC);
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client->secs = 0;
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return client_initialize_events(client, client->start_time);
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return client_initialize_events(client, client_receive_message_udp,
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client->start_time);
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}
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int sd_dhcp_client_stop(sd_dhcp_client *client) {
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return client_stop(client, DHCP_EVENT_STOP);
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}
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int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int priority) {
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int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
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int priority) {
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int r;
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assert_return(client, -EINVAL);
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