libsystemd-dhcp: Handle T1 Renewing timeout
Expiration of T1 timeout takes the client to the Rebinding state, where it attempts to renew its lease. Start by opening a DCHP unicast socket as there now is a proper IP address set. Compute the resend timer as half of the remaining time down to a minimum of 60 seconds (RFC2131). Modify DHCP Request sending to send only UDP DHCP data when unicasting. Also modify DHCP Ack/Nak receiving such that the client_receive_ack() takes care of using either the full IP, UDP, DHCP packet or only the DHCP payload depending whether the client is in Requesting or Renewing state. Finally always report DHCP_EVENT_IP_ACQUIRE from Requesting state and only DHCP_EVENT_IP_CHANGE if the IP address was modified when the lease was renewed.
This commit is contained in:
Patrik Flykt
Tom Gundersen
parent
234fc2dfce
commit
aba26854e5
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@ -22,6 +22,7 @@
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#include <string.h>
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#include <stdio.h>
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#include <net/ethernet.h>
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#include <sys/param.h>
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#include "util.h"
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#include "list.h"
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@ -77,6 +78,9 @@ 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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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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{
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@ -324,6 +328,9 @@ static int client_packet_init(sd_dhcp_client *client, uint8_t type,
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refuse to issue an DHCP lease if 'secs' is set to zero */
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message->secs = htobe16(secs);
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if (client->state == DHCP_STATE_RENEWING)
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message->ciaddr = client->lease->address;
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memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
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(*opt)[0] = 0x63;
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(*opt)[1] = 0x82;
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@ -490,10 +497,17 @@ static int client_send_request(sd_dhcp_client *client, uint16_t secs)
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if (err < 0)
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return err;
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client_append_ip_headers(request, len);
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if (client->state == DHCP_STATE_RENEWING) {
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err = dhcp_network_send_udp_socket(client->fd,
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client->lease->server_address,
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&request->dhcp,
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len - DHCP_IP_UDP_SIZE);
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} else {
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client_append_ip_headers(request, len);
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err = dhcp_network_send_raw_socket(client->fd, &client->link,
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request, len);
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err = dhcp_network_send_raw_socket(client->fd, &client->link,
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request, len);
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}
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return err;
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}
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@ -502,17 +516,39 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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void *userdata)
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{
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sd_dhcp_client *client = userdata;
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usec_t next_timeout;
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usec_t next_timeout = 0;
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uint32_t time_left;
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uint16_t secs;
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int err = 0;
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secs = (usec - client->start_time) / USEC_PER_SEC;
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switch (client->state) {
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case DHCP_STATE_RENEWING:
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if (client->attempt < 64)
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client->attempt *= 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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next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
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(random_u() & 0x1fffff);
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next_timeout = usec + time_left * USEC_PER_SEC;
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break;
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case DHCP_STATE_INIT:
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_SELECTING:
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case DHCP_STATE_REQUESTING:
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case DHCP_STATE_BOUND:
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case DHCP_STATE_REBINDING:
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if (client->attempt < 64)
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client->attempt *= 2;
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next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
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break;
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}
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next_timeout += (random_u() & 0x1fffff);
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err = sd_event_add_monotonic(client->event, next_timeout,
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10 * USEC_PER_MSEC,
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@ -521,6 +557,8 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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if (err < 0)
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goto error;
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secs = (usec - client->start_time) / USEC_PER_SEC;
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switch (client->state) {
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case DHCP_STATE_INIT:
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err = client_send_discover(client, secs);
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@ -542,6 +580,7 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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break;
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case DHCP_STATE_REQUESTING:
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case DHCP_STATE_RENEWING:
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err = client_send_request(client, secs);
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if (err < 0 && client->attempt >= 64)
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goto error;
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@ -553,7 +592,6 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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break;
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@ -586,6 +624,35 @@ static int client_timeout_t2(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, void *userdata)
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{
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sd_dhcp_client *client = userdata;
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int r;
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client->state = DHCP_STATE_RENEWING;
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client->attempt = 1;
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r = dhcp_network_bind_udp_socket(client->index,
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client->lease->address);
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if (r < 0)
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goto error;
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client->fd = r;
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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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if (r < 0)
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goto error;
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r = sd_event_add_monotonic(client->event, usec, 0,
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client_timeout_resend, client,
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&client->timeout_resend);
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if (r < 0)
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goto error;
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return 0;
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error:
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client_stop(client, r);
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return 0;
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}
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@ -717,22 +784,32 @@ error:
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return -ENOMSG;
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}
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static int client_receive_ack(sd_dhcp_client *client, DHCPPacket *offer,
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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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{
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int r;
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DHCPPacket *ack;
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DHCPMessage *dhcp;
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DHCPLease *lease;
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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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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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lease = new0(DHCPLease, 1);
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if (!lease)
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return -ENOMEM;
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len = len - DHCP_IP_UDP_SIZE;
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r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer, lease);
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r = dhcp_option_parse(dhcp, len, client_parse_offer, lease);
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if (r == DHCP_NAK) {
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r = DHCP_EVENT_NO_LEASE;
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@ -744,7 +821,7 @@ static int client_receive_ack(sd_dhcp_client *client, DHCPPacket *offer,
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goto error;
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}
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lease->address = offer->dhcp.yiaddr;
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lease->address = dhcp->yiaddr;
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if (lease->address == INADDR_ANY ||
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lease->server_address == INADDR_ANY ||
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@ -789,6 +866,10 @@ static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
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if (client->lease->lifetime < 10)
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return -EINVAL;
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client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
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client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
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client->timeout_expire = sd_event_source_unref(client->timeout_expire);
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if (!client->lease->t1)
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client->lease->t1 = client->lease->lifetime / 2;
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@ -840,13 +921,13 @@ static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
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return 0;
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}
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static int client_receive_raw_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(sd_event_source *s, int fd,
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uint32_t revents, void *userdata)
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{
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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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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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@ -858,11 +939,11 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
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if (r < 0)
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goto error;
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message = (DHCPPacket *)&buf;
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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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client->timeout_resend =
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@ -882,8 +963,10 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
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break;
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case DHCP_STATE_REQUESTING:
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case DHCP_STATE_RENEWING:
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r = client_receive_ack(client, buf, len);
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r = client_receive_ack(client, message, len);
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if (r == DHCP_EVENT_NO_LEASE)
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goto error;
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@ -891,16 +974,22 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
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client->timeout_resend =
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sd_event_source_unref(client->timeout_resend);
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if (client->state == DHCP_STATE_REQUESTING)
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notify_event = DHCP_EVENT_IP_ACQUIRE;
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else if (r != DHCP_EVENT_IP_ACQUIRE)
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notify_event = r;
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client->state = DHCP_STATE_BOUND;
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client->attempt = 1;
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client->last_addr = client->lease->address;
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r = client_set_lease_timeouts(client, time_now);
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if (r < 0 )
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if (r < 0)
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goto error;
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client_notify(client, DHCP_EVENT_IP_ACQUIRE);
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if (notify_event)
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client_notify(client, notify_event);
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client->receive_message =
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sd_event_source_unref(client->receive_message);
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@ -916,7 +1005,6 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
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case DHCP_STATE_INIT_REBOOT:
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case DHCP_STATE_REBOOTING:
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case DHCP_STATE_BOUND:
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case DHCP_STATE_RENEWING:
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case DHCP_STATE_REBINDING:
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break;
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@ -949,7 +1037,7 @@ int sd_dhcp_client_start(sd_dhcp_client *client)
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}
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err = sd_event_add_io(client->event, client->fd, EPOLLIN,
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client_receive_raw_message, client,
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client_receive_message, client,
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&client->receive_message);
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if (err < 0)
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goto error;
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