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path: root/src/libsystemd-dhcp/dhcp-client.c
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Diffstat (limited to 'src/libsystemd-dhcp/dhcp-client.c')
-rw-r--r--src/libsystemd-dhcp/dhcp-client.c160
1 files changed, 121 insertions, 39 deletions
diff --git a/src/libsystemd-dhcp/dhcp-client.c b/src/libsystemd-dhcp/dhcp-client.c
index d3ba7ae8ed..4980174e00 100644
--- a/src/libsystemd-dhcp/dhcp-client.c
+++ b/src/libsystemd-dhcp/dhcp-client.c
@@ -56,6 +56,7 @@ struct sd_dhcp_client {
struct ether_addr mac_addr;
uint32_t xid;
usec_t start_time;
+ unsigned int attempt;
DHCPLease *lease;
};
@@ -151,6 +152,8 @@ static int client_stop(sd_dhcp_client *client, int error)
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+ client->attempt = 1;
+
switch (client->state) {
case DHCP_STATE_INIT:
@@ -252,6 +255,28 @@ static uint16_t client_checksum(void *buf, int len)
return ~((sum & 0xffff) + (sum >> 16));
}
+static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
+{
+ packet->ip.version = IPVERSION;
+ packet->ip.ihl = DHCP_IP_SIZE / 4;
+ packet->ip.tot_len = htobe16(len);
+
+ packet->ip.protocol = IPPROTO_UDP;
+ packet->ip.saddr = INADDR_ANY;
+ packet->ip.daddr = INADDR_BROADCAST;
+
+ packet->udp.source = htobe16(DHCP_PORT_CLIENT);
+ packet->udp.dest = htobe16(DHCP_PORT_SERVER);
+ packet->udp.len = htobe16(len - DHCP_IP_SIZE);
+
+ packet->ip.check = packet->udp.len;
+ packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
+
+ packet->ip.ttl = IPDEFTTL;
+ packet->ip.check = 0;
+ packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
+}
+
static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
{
int err = 0;
@@ -284,29 +309,55 @@ static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
if (err < 0)
return err;
- discover->ip.version = IPVERSION;
- discover->ip.ihl = sizeof(discover->ip) >> 2;
- discover->ip.tot_len = htobe16(len);
+ client_append_ip_headers(discover, len);
+
+ err = dhcp_network_send_raw_socket(client->fd, &client->link,
+ discover, len);
+
+ return err;
+}
+
+static int client_send_request(sd_dhcp_client *client, uint16_t secs)
+{
+ _cleanup_free_ DHCPPacket *request;
+ size_t optlen, len;
+ int err;
+ uint8_t *opt;
+
+ optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
+ len = DHCP_MESSAGE_SIZE + optlen;
+
+ request = malloc0(len);
+ if (!request)
+ return -ENOMEM;
+
+ err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
+ &opt, &optlen);
+ if (err < 0)
+ return err;
- discover->ip.protocol = IPPROTO_UDP;
- discover->ip.saddr = INADDR_ANY;
- discover->ip.daddr = INADDR_BROADCAST;
+ if (client->state == DHCP_STATE_REQUESTING) {
+ err = dhcp_option_append(&opt, &optlen,
+ DHCP_OPTION_REQUESTED_IP_ADDRESS,
+ 4, &client->lease->address);
+ if (err < 0)
+ return err;
- discover->udp.source = htobe16(DHCP_PORT_CLIENT);
- discover->udp.dest = htobe16(DHCP_PORT_SERVER);
- discover->udp.len = htobe16(len - sizeof(discover->ip));
+ err = dhcp_option_append(&opt, &optlen,
+ DHCP_OPTION_SERVER_IDENTIFIER,
+ 4, &client->lease->server_address);
+ if (err < 0)
+ return err;
+ }
- discover->ip.check = discover->udp.len;
- discover->udp.check = client_checksum(&discover->ip.ttl,
- len - 8);
+ err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
+ if (err < 0)
+ return err;
- discover->ip.ttl = IPDEFTTL;
- discover->ip.check = 0;
- discover->ip.check = client_checksum(&discover->ip,
- sizeof(discover->ip));
+ client_append_ip_headers(request, len);
err = dhcp_network_send_raw_socket(client->fd, &client->link,
- discover, len);
+ request, len);
return err;
}
@@ -319,32 +370,50 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
uint16_t secs;
int err = 0;
- switch (client->state) {
- case DHCP_STATE_INIT:
- case DHCP_STATE_SELECTING:
+ secs = (usec - client->start_time) / USEC_PER_SEC;
- if (!client->start_time)
- client->start_time = usec;
+ if (client->attempt < 64)
+ client->attempt *= 2;
- secs = (usec - client->start_time) / USEC_PER_SEC;
+ next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
+ (random_u() & 0x1fffff);
- next_timeout = usec + 2 * USEC_PER_SEC + (random() & 0x1fffff);
+ err = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_resend, client,
+ &client->timeout_resend);
+ if (err < 0)
+ goto error;
- err = sd_event_add_monotonic(client->event, next_timeout,
- 10 * USEC_PER_MSEC,
- client_timeout_resend, client,
- &client->timeout_resend);
- if (err < 0)
+ switch (client->state) {
+ case DHCP_STATE_INIT:
+ err = client_send_discover(client, secs);
+ if (err >= 0) {
+ client->state = DHCP_STATE_SELECTING;
+ client->attempt = 1;
+ } else {
+ if (client->attempt >= 64)
+ goto error;
+ }
+
+ break;
+
+ case DHCP_STATE_SELECTING:
+ err = client_send_discover(client, secs);
+ if (err < 0 && client->attempt >= 64)
goto error;
- if (client_send_discover(client, secs) >= 0)
- client->state = DHCP_STATE_SELECTING;
+ break;
+
+ case DHCP_STATE_REQUESTING:
+ err = client_send_request(client, secs);
+ if (err < 0 && client->attempt >= 64)
+ goto error;
break;
case DHCP_STATE_INIT_REBOOT:
case DHCP_STATE_REBOOTING:
- case DHCP_STATE_REQUESTING:
case DHCP_STATE_BOUND:
case DHCP_STATE_RENEWING:
case DHCP_STATE_REBINDING:
@@ -468,11 +537,16 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
sd_dhcp_client *client = userdata;
uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
int buflen = sizeof(buf);
- int len;
+ int len, err = 0;
DHCPPacket *message;
+ usec_t time_now;
len = read(fd, &buf, buflen);
if (len < 0)
+ return 0;
+
+ err = sd_event_get_now_monotonic(client->event, &time_now);
+ if (err < 0)
goto error;
message = (DHCPPacket *)&buf;
@@ -482,15 +556,18 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
if (client_receive_offer(client, message, len) >= 0) {
- client->receive_message =
- sd_event_source_unref(client->receive_message);
- close(client->fd);
- client->fd = -1;
-
client->timeout_resend =
sd_event_source_unref(client->timeout_resend);
client->state = DHCP_STATE_REQUESTING;
+ client->attempt = 1;
+
+ err = sd_event_add_monotonic(client->event, time_now, 0,
+ client_timeout_resend,
+ client,
+ &client->timeout_resend);
+ if (err < 0)
+ goto error;
}
break;
@@ -507,6 +584,9 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
}
error:
+ if (err < 0)
+ return client_stop(client, err);
+
return 0;
}
@@ -535,7 +615,8 @@ int sd_dhcp_client_start(sd_dhcp_client *client)
if (err < 0)
goto error;
- err = sd_event_add_monotonic(client->event, now(CLOCK_MONOTONIC), 0,
+ client->start_time = now(CLOCK_MONOTONIC);
+ err = sd_event_add_monotonic(client->event, client->start_time, 0,
client_timeout_resend, client,
&client->timeout_resend);
if (err < 0)
@@ -568,6 +649,7 @@ sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
client->state = DHCP_STATE_INIT;
client->index = -1;
client->fd = -1;
+ client->attempt = 1;
client->req_opts_size = ELEMENTSOF(default_req_opts);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-18 05:50:04 +0000