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authorPatrik Flykt <patrik.flykt@linux.intel.com>2013-12-09 23:43:26 +0200
committerZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>2013-12-12 11:43:34 -0500
commit8c00042c939938818365753023ff2d50f984dec6 (patch)
treeafffca11004c504d8c6e98ca3efea1d8911e8f13 /src/libsystemd-dhcp/dhcp-client.c
parentd3d8ac2f2bac721d99f893c0a0128d21db636d4c (diff)
dhcp: Handle received DHCP Offer message
Create a function for handling the full IP, UDP and DHCP packet and tie it to the main loop. Verify IP and UDP headers and checksum. Creat a new lease structure with using the values supplied in the DHCP message. Free the lease structure when client is stopped. Split out socket handling into a creation and a sending part. As a result modify the test code.
Diffstat (limited to 'src/libsystemd-dhcp/dhcp-client.c')
-rw-r--r--src/libsystemd-dhcp/dhcp-client.c195
1 files changed, 193 insertions, 2 deletions
diff --git a/src/libsystemd-dhcp/dhcp-client.c b/src/libsystemd-dhcp/dhcp-client.c
index e9c4700081..d3ba7ae8ed 100644
--- a/src/libsystemd-dhcp/dhcp-client.c
+++ b/src/libsystemd-dhcp/dhcp-client.c
@@ -32,17 +32,31 @@
#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
+struct DHCPLease {
+ uint32_t lifetime;
+ uint32_t address;
+ uint32_t server_address;
+ uint32_t subnet_mask;
+ uint32_t router;
+};
+
+typedef struct DHCPLease DHCPLease;
+
struct sd_dhcp_client {
DHCPState state;
sd_event *event;
sd_event_source *timeout_resend;
int index;
+ int fd;
+ union sockaddr_union link;
+ sd_event_source *receive_message;
uint8_t *req_opts;
size_t req_opts_size;
uint32_t last_addr;
struct ether_addr mac_addr;
uint32_t xid;
usec_t start_time;
+ DHCPLease *lease;
};
static const uint8_t default_req_opts[] = {
@@ -128,6 +142,13 @@ static int client_stop(sd_dhcp_client *client, int error)
assert_return(client->state != DHCP_STATE_INIT &&
client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
+ client->receive_message =
+ sd_event_source_unref(client->receive_message);
+
+ if (client->fd >= 0)
+ close(client->fd);
+ client->fd = -1;
+
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
switch (client->state) {
@@ -135,6 +156,7 @@ static int client_stop(sd_dhcp_client *client, int error)
case DHCP_STATE_INIT:
case DHCP_STATE_SELECTING:
+ client->start_time = 0;
client->state = DHCP_STATE_INIT;
break;
@@ -148,6 +170,11 @@ static int client_stop(sd_dhcp_client *client, int error)
break;
}
+ if (client->lease) {
+ free(client->lease);
+ client->lease = NULL;
+ }
+
return 0;
}
@@ -278,9 +305,10 @@ static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
discover->ip.check = client_checksum(&discover->ip,
sizeof(discover->ip));
- err = dhcp_network_send_raw_packet(client->index, discover, len);
+ err = dhcp_network_send_raw_socket(client->fd, &client->link,
+ discover, len);
- return 0;
+ return err;
}
static int client_timeout_resend(sd_event_source *s, uint64_t usec,
@@ -334,6 +362,154 @@ error:
return 0;
}
+static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
+ void *user_data)
+{
+ DHCPLease *lease = user_data;
+ be32_t val;
+
+ switch(code) {
+
+ case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
+ if (len == 4) {
+ memcpy(&val, option, 4);
+ lease->lifetime = be32toh(val);
+ }
+
+ break;
+
+ case DHCP_OPTION_SERVER_IDENTIFIER:
+ if (len >= 4)
+ memcpy(&lease->server_address, option, 4);
+
+ break;
+
+ case DHCP_OPTION_SUBNET_MASK:
+ if (len >= 4)
+ memcpy(&lease->subnet_mask, option, 4);
+
+ break;
+
+ case DHCP_OPTION_ROUTER:
+ if (len >= 4)
+ memcpy(&lease->router, option, 4);
+
+ break;
+ }
+
+ return 0;
+}
+
+static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
+ size_t len)
+{
+ size_t hdrlen;
+ DHCPLease *lease;
+
+ if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
+ return -EINVAL;
+
+ hdrlen = offer->ip.ihl * 4;
+ if (hdrlen < 20 || hdrlen > len || client_checksum(&offer->ip,
+ hdrlen))
+ return -EINVAL;
+
+ offer->ip.check = offer->udp.len;
+ offer->ip.ttl = 0;
+
+ if (hdrlen + be16toh(offer->udp.len) > len ||
+ client_checksum(&offer->ip.ttl, be16toh(offer->udp.len) + 12))
+ return -EINVAL;
+
+ if (be16toh(offer->udp.source) != DHCP_PORT_SERVER ||
+ be16toh(offer->udp.dest) != DHCP_PORT_CLIENT)
+ return -EINVAL;
+
+ if (offer->dhcp.op != BOOTREPLY)
+ return -EINVAL;
+
+ if (be32toh(offer->dhcp.xid) != client->xid)
+ return -EINVAL;
+
+ if (memcmp(&offer->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
+ ETHER_ADDR_LEN))
+ return -EINVAL;
+
+ lease = new0(DHCPLease, 1);
+ if (!lease)
+ return -ENOMEM;
+
+ len = len - DHCP_IP_UDP_SIZE;
+ if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
+ lease) != DHCP_OFFER)
+ goto error;
+
+ lease->address = offer->dhcp.yiaddr;
+
+ if (lease->address == INADDR_ANY ||
+ lease->server_address == INADDR_ANY ||
+ lease->subnet_mask == INADDR_ANY ||
+ lease->lifetime == 0)
+ goto error;
+
+ client->lease = lease;
+
+ return 0;
+
+error:
+ free(lease);
+
+ return -ENOMSG;
+}
+
+static int client_receive_raw_message(sd_event_source *s, int fd,
+ uint32_t revents, void *userdata)
+{
+ sd_dhcp_client *client = userdata;
+ uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
+ int buflen = sizeof(buf);
+ int len;
+ DHCPPacket *message;
+
+ len = read(fd, &buf, buflen);
+ if (len < 0)
+ goto error;
+
+ message = (DHCPPacket *)&buf;
+
+ switch (client->state) {
+ case DHCP_STATE_SELECTING:
+
+ 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;
+ }
+
+ break;
+
+ case DHCP_STATE_INIT:
+ 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:
+
+ break;
+ }
+
+error:
+ return 0;
+}
+
int sd_dhcp_client_start(sd_dhcp_client *client)
{
int err;
@@ -345,6 +521,20 @@ int sd_dhcp_client_start(sd_dhcp_client *client)
client->xid = random_u();
+ client->fd = dhcp_network_bind_raw_socket(client->index,
+ &client->link);
+
+ if (client->fd < 0) {
+ err = client->fd;
+ goto error;
+ }
+
+ err = sd_event_add_io(client->event, client->fd, EPOLLIN,
+ client_receive_raw_message, client,
+ &client->receive_message);
+ if (err < 0)
+ goto error;
+
err = sd_event_add_monotonic(client->event, now(CLOCK_MONOTONIC), 0,
client_timeout_resend, client,
&client->timeout_resend);
@@ -377,6 +567,7 @@ sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
client->event = sd_event_ref(event);
client->state = DHCP_STATE_INIT;
client->index = -1;
+ client->fd = -1;
client->req_opts_size = ELEMENTSOF(default_req_opts);