From 51debc1e396a14d7c1204d8661c4eb1056c47670 Mon Sep 17 00:00:00 2001 From: Patrik Flykt Date: Mon, 9 Dec 2013 23:43:30 +0200 Subject: [PATCH] dhcp: Compute expire, T1 and T2 timers Compute the default T1 and T2 timer values if they were not set by the DHCP server. Verify that the values are reasonable. --- src/libsystemd-dhcp/dhcp-client.c | 116 +++++++++++++++++++++++++++- src/libsystemd-dhcp/dhcp-protocol.h | 2 + 2 files changed, 117 insertions(+), 1 deletion(-) diff --git a/src/libsystemd-dhcp/dhcp-client.c b/src/libsystemd-dhcp/dhcp-client.c index a15866932..d03435b92 100644 --- a/src/libsystemd-dhcp/dhcp-client.c +++ b/src/libsystemd-dhcp/dhcp-client.c @@ -33,6 +33,8 @@ #define DHCP_CLIENT_MIN_OPTIONS_SIZE 312 struct DHCPLease { + uint32_t t1; + uint32_t t2; uint32_t lifetime; uint32_t address; uint32_t server_address; @@ -57,6 +59,10 @@ struct sd_dhcp_client { uint32_t xid; usec_t start_time; unsigned int attempt; + usec_t request_sent; + sd_event_source *timeout_t1; + sd_event_source *timeout_t2; + sd_event_source *timeout_expire; DHCPLease *lease; }; @@ -157,6 +163,10 @@ static int client_stop(sd_dhcp_client *client, int error) client->timeout_resend = sd_event_source_unref(client->timeout_resend); + client->timeout_t1 = sd_event_source_unref(client->timeout_t1); + client->timeout_t2 = sd_event_source_unref(client->timeout_t2); + client->timeout_expire = sd_event_source_unref(client->timeout_expire); + client->attempt = 1; switch (client->state) { @@ -164,6 +174,7 @@ static int client_stop(sd_dhcp_client *client, int error) case DHCP_STATE_INIT: case DHCP_STATE_SELECTING: case DHCP_STATE_REQUESTING: + case DHCP_STATE_BOUND: client->start_time = 0; client->state = DHCP_STATE_INIT; @@ -171,7 +182,6 @@ static int client_stop(sd_dhcp_client *client, int error) case DHCP_STATE_INIT_REBOOT: case DHCP_STATE_REBOOTING: - case DHCP_STATE_BOUND: case DHCP_STATE_RENEWING: case DHCP_STATE_REBINDING: @@ -427,6 +437,8 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec, if (err < 0 && client->attempt >= 64) goto error; + client->request_sent = usec; + break; case DHCP_STATE_INIT_REBOOT: @@ -448,6 +460,22 @@ error: return 0; } +static int client_timeout_expire(sd_event_source *s, uint64_t usec, + void *userdata) +{ + return 0; +} + +static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) +{ + return 0; +} + +static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) +{ + return 0; +} + static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option, void *user_data) { @@ -481,6 +509,22 @@ static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option, memcpy(&lease->router, option, 4); break; + + case DHCP_OPTION_RENEWAL_T1_TIME: + if (len == 4) { + memcpy(&val, option, 4); + lease->t1 = be32toh(val); + } + + break; + + case DHCP_OPTION_REBINDING_T2_TIME: + if (len == 4) { + memcpy(&val, option, 4); + lease->t2 = be32toh(val); + } + + break; } return 0; @@ -610,6 +654,72 @@ error: return r; } +static uint64_t client_compute_timeout(uint64_t request_sent, + uint32_t lifetime) +{ + return request_sent + (lifetime - 3) * USEC_PER_SEC + + + (random_u() & 0x1fffff); +} + +static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) +{ + int err; + uint64_t next_timeout; + + if (client->lease->lifetime < 10) + return -EINVAL; + + if (!client->lease->t1) + client->lease->t1 = client->lease->lifetime / 2; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->t1); + if (next_timeout < usec) + return -EINVAL; + + err = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t1, client, + &client->timeout_t1); + if (err < 0) + return err; + + if (!client->lease->t2) + client->lease->t2 = client->lease->lifetime * 7 / 8; + + if (client->lease->t2 < client->lease->t1) + return -EINVAL; + + if (client->lease->lifetime < client->lease->t2) + return -EINVAL; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->t2); + if (next_timeout < usec) + return -EINVAL; + + err = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_t2, client, + &client->timeout_t2); + if (err < 0) + return err; + + next_timeout = client_compute_timeout(client->request_sent, + client->lease->lifetime); + if (next_timeout < usec) + return -EINVAL; + + err = sd_event_add_monotonic(client->event, next_timeout, + 10 * USEC_PER_MSEC, + client_timeout_expire, client, + &client->timeout_expire); + if (err < 0) + return err; + + return 0; +} + static int client_receive_raw_message(sd_event_source *s, int fd, uint32_t revents, void *userdata) { @@ -666,6 +776,10 @@ static int client_receive_raw_message(sd_event_source *s, int fd, client->last_addr = client->lease->address; + r = client_set_lease_timeouts(client, time_now); + if (r < 0 ) + goto error; + client_notify(client, DHCP_EVENT_IP_ACQUIRE); close(client->fd); diff --git a/src/libsystemd-dhcp/dhcp-protocol.h b/src/libsystemd-dhcp/dhcp-protocol.h index f5f490d8b..1e59965dc 100644 --- a/src/libsystemd-dhcp/dhcp-protocol.h +++ b/src/libsystemd-dhcp/dhcp-protocol.h @@ -112,6 +112,8 @@ enum { DHCP_OPTION_SERVER_IDENTIFIER = 54, DHCP_OPTION_PARAMETER_REQUEST_LIST = 55, DHCP_OPTION_MAXIMUM_MESSAGE_SIZE = 57, + DHCP_OPTION_RENEWAL_T1_TIME = 58, + DHCP_OPTION_REBINDING_T2_TIME = 59, DHCP_OPTION_CLIENT_IDENTIFIER = 61, DHCP_OPTION_END = 255, }; -- 2.30.2