/**
* pass_to_client() - forwards dhcp packets from server to client
* p - packet to send
*/
static void pass_to_client(struct dhcp_packet *p, int packet_len, int *fds)
{
int type;
struct xid_item *item;
/* check xid */
item = xid_find(p->xid);
if (!item) {
return;
}
/* check packet type */
type = get_dhcp_packet_type(p);
if (type != DHCPOFFER && type != DHCPACK && type != DHCPNAK) {
return;
}
//TODO: also do it if (p->flags & htons(BROADCAST_FLAG)) is set!
if (item->ip.sin_addr.s_addr == htonl(INADDR_ANY))
item->ip.sin_addr.s_addr = htonl(INADDR_BROADCAST);
if (sendto_ip4(fds[item->client], p, packet_len, &item->ip) != 0) {
return; /* send error occurred */
}
/* remove xid entry */
xid_del(p->xid);
}
/**
* pass_back() - forwards dhcp packets from server to client
* p - packet to send
*/
static void pass_back(struct dhcpMessage *p, int packet_len, int *fds)
{
int res, type;
struct xid_item *item;
/* check xid */
item = xid_find(p->xid);
if (!item) {
return;
}
/* check packet type */
type = get_dhcp_packet_type(p);
if (type != DHCPOFFER && type != DHCPACK && type != DHCPNAK) {
return;
}
if (item->ip.sin_addr.s_addr == htonl(INADDR_ANY))
item->ip.sin_addr.s_addr = htonl(INADDR_BROADCAST);
if (item->client > MAX_INTERFACES)
return;
res = sendto(fds[item->client], p, packet_len, 0, (struct sockaddr*)(&item->ip),
sizeof(item->ip));
if (res != packet_len) {
bb_perror_msg("pass_back");
return;
}
/* remove xid entry */
xid_del(p->xid);
}
/**
* pass_on() - forwards dhcp packets from client to server
* p - packet to send
* client - number of the client
*/
static void pass_on(struct dhcpMessage *p, int packet_len, int client, int *fds,
struct sockaddr_in *client_addr, struct sockaddr_in *server_addr)
{
int res, type;
struct xid_item *item;
/* check packet_type */
type = get_dhcp_packet_type(p);
if (type != DHCPDISCOVER && type != DHCPREQUEST
&& type != DHCPDECLINE && type != DHCPRELEASE
&& type != DHCPINFORM
) {
return;
}
/* create new xid entry */
item = xid_add(p->xid, client_addr, client);
/* forward request to LAN (server) */
res = sendto(fds[0], p, packet_len, 0, (struct sockaddr*)server_addr,
sizeof(struct sockaddr_in));
if (res != packet_len) {
bb_perror_msg("pass_on");
return;
}
}
/**
* pass_to_server() - forwards dhcp packets from client to server
* p - packet to send
* client - number of the client
*/
static void pass_to_server(struct dhcp_packet *p, int packet_len, int client, int *fds,
struct sockaddr_in *client_addr, struct sockaddr_in *server_addr)
{
int type;
/* check packet_type */
type = get_dhcp_packet_type(p);
if (type != DHCPDISCOVER && type != DHCPREQUEST
&& type != DHCPDECLINE && type != DHCPRELEASE
&& type != DHCPINFORM
) {
return;
}
/* create new xid entry */
xid_add(p->xid, client_addr, client);
/* forward request to server */
/* note that we send from fds[0] which is bound to SERVER_PORT (67).
* IOW: we send _from_ SERVER_PORT! Although this may look strange,
* RFC 1542 not only allows, but prescribes this for BOOTP relays.
*/
sendto_ip4(fds[0], p, packet_len, server_addr);
}
