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dhcpserver: Add expiry, DHCPNAK packets

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This commit is contained in:
Angus Gratton 2015-08-24 16:13:24 +10:00
parent 4c98f575e7
commit 9fc223b3c2
2 changed files with 47 additions and 2 deletions
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47
extras/dhcpserver/dhcpserver.c
View file

@ -29,6 +29,9 @@ typedef struct {
/* Handlers for various kinds of incoming DHCP messages */
static void handle_dhcp_discover(server_state_t *state, struct dhcp_msg *received);
static void handle_dhcp_request(server_state_t *state, struct dhcp_msg *dhcpmsg);
static void handle_dhcp_release(server_state_t *state, struct dhcp_msg *dhcpmsg);
static void send_dhcp_nak(server_state_t *state, struct dhcp_msg *dhcpmsg);
/* Utility functions */
static uint8_t *find_dhcp_option(struct dhcp_msg *msg, uint8_t option_num, uint8_t min_length, uint8_t *length);
@ -62,12 +65,22 @@ static void dhcpserver_task(void *pxParameter)
{
struct netbuf *netbuf;
struct dhcp_msg received = { 0 };
/* Receive a DHCP packet */
err_t err = netconn_recv(state.nc, &netbuf);
if(err != ERR_OK) {
printf("DHCP Server Error: Failed to receive DHCP packet. err=%d\r\n", err);
continue;
}
/* expire any leases that have passed */
uint32_t now = xTaskGetTickCount();
for(int i = 0; i < DHCPSERVER_MAXCLIENTS; i++) {
uint32_t expires = state.leases[i].expires;
if(expires && expires < now)
state.leases[i].expires = 0;
}
ip_addr_t received_ip;
u16_t port;
netconn_addr(state.nc, &received_ip, &port);
@ -98,6 +111,8 @@ static void dhcpserver_task(void *pxParameter)
case DHCP_REQUEST:
handle_dhcp_request(&state, &received);
break;
case DHCP_RELEASE:
handle_dhcp_release(&state, &received);
default:
printf("DHCP Server Error: Unsupported message type %d\r\n", *message_type);
break;
@ -155,6 +170,7 @@ static void handle_dhcp_request(server_state_t *state, struct dhcp_msg *dhcpmsg)
ip_addr_copy(requested_ip, dhcpmsg->ciaddr);
} else {
printf("DHCP Server Error: No requested IP\r\n");
send_dhcp_nak(state, dhcpmsg);
return;
}
ip_addr_t first_client_ip;
@ -165,12 +181,14 @@ static void handle_dhcp_request(server_state_t *state, struct dhcp_msg *dhcpmsg)
|| ip4_addr2(&requested_ip) != ip4_addr2(&first_client_ip)
|| ip4_addr3(&requested_ip) != ip4_addr3(&first_client_ip)) {
printf("DHCP Server Error: 0x%08lx Not an allowed IP\r\n", requested_ip.addr);
send_dhcp_nak(state, dhcpmsg);
return;
}
/* Test the last octet is in the MAXCLIENTS range */
int16_t octet_offs = ip4_addr4(&requested_ip) - ip4_addr4(&first_client_ip);
if(octet_offs < 0 || octet_offs >= DHCPSERVER_MAXCLIENTS) {
printf("DHCP Server Error: Address out of range\r\n");
send_dhcp_nak(state, dhcpmsg);
return;
}
@ -178,6 +196,7 @@ static void handle_dhcp_request(server_state_t *state, struct dhcp_msg *dhcpmsg)
if(requested_lease->expires != 0 && memcmp(requested_lease->hwaddr, dhcpmsg->chaddr,dhcpmsg->hlen))
{
printf("DHCP Server Error: Lease for address already taken\r\n");
send_dhcp_nak(state, dhcpmsg);
return;
}
@ -185,7 +204,7 @@ static void handle_dhcp_request(server_state_t *state, struct dhcp_msg *dhcpmsg)
printf("DHCP lease addr 0x%08lx assigned to MAC %02x:%02x:%02x:%02x:%02x:%02x\r\n", requested_ip.addr, requested_lease->hwaddr[0],
requested_lease->hwaddr[1], requested_lease->hwaddr[2], requested_lease->hwaddr[3], requested_lease->hwaddr[4],
requested_lease->hwaddr[5]);
requested_lease->expires = 1;
requested_lease->expires = DHCPSERVER_LEASE_TIME * configTICK_RATE_HZ;
/* Reuse the REQUEST message as the ACK message */
dhcpmsg->op = DHCP_BOOTREPLY;
@ -207,6 +226,32 @@ static void handle_dhcp_request(server_state_t *state, struct dhcp_msg *dhcpmsg)
netbuf_delete(netbuf);
}
static void handle_dhcp_release(server_state_t *state, struct dhcp_msg *dhcpmsg)
{
dhcp_lease_t *lease = find_lease_slot(state->leases, dhcpmsg->chaddr);
if(lease) {
lease->expires = 0;
}
}
static void send_dhcp_nak(server_state_t *state, struct dhcp_msg *dhcpmsg)
{
/* Reuse 'dhcpmsg' for the NAK */
dhcpmsg->op = DHCP_BOOTREPLY;
bzero(dhcpmsg->options, DHCP_OPTIONS_LEN);
uint8_t *opt = (uint8_t *)&dhcpmsg->options;
opt = add_dhcp_option_byte(opt, DHCP_OPTION_MESSAGE_TYPE, DHCP_NAK);
opt = add_dhcp_option_bytes(opt, DHCP_OPTION_SERVER_ID, &state->server_if->ip_addr, 4);
opt = add_dhcp_option_bytes(opt, DHCP_OPTION_END, NULL, 0);
struct netbuf *netbuf = netbuf_new();
netbuf_alloc(netbuf, sizeof(struct dhcp_msg));
netbuf_take(netbuf, dhcpmsg, sizeof(struct dhcp_msg));
netconn_sendto(state->nc, netbuf, IP_ADDR_BROADCAST, 68);
netbuf_delete(netbuf);
}
static uint8_t *find_dhcp_option(struct dhcp_msg *msg, uint8_t option_num, uint8_t min_length, uint8_t *length)
{
uint8_t *start = (uint8_t *)&msg->options;

2
extras/dhcpserver/include/dhcpserver.h
View file

@ -18,7 +18,7 @@
#endif
#ifndef DHCPSERVER_LEASE_TIME
#define DHCPSERVER_LEASE_TIME 30
#define DHCPSERVER_LEASE_TIME 3600
#endif
/* Start DHCP server.