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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright (C) 2013 Intel Corporation. All rights reserved.
Copyright (C) 2014 Tom Gundersen
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/ioctl.h>
#include "sd-dhcp-server.h"
#include "dhcp-server-internal.h"
#include "dhcp-internal.h"
sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) {
if (server)
assert_se(REFCNT_INC(server->n_ref) >= 2);
return server;
}
sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) {
if (server && REFCNT_DEC(server->n_ref) <= 0) {
log_dhcp_server(server, "UNREF");
sd_dhcp_server_stop(server);
sd_event_unref(server->event);
free(server);
}
return NULL;
}
int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) {
_cleanup_dhcp_server_unref_ sd_dhcp_server *server = NULL;
assert_return(ret, -EINVAL);
assert_return(ifindex > 0, -EINVAL);
server = new0(sd_dhcp_server, 1);
if (!server)
return -ENOMEM;
server->n_ref = REFCNT_INIT;
server->fd = -1;
server->index = ifindex;
*ret = server;
server = NULL;
return 0;
}
int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, int priority) {
int r;
assert_return(server, -EINVAL);
assert_return(!server->event, -EBUSY);
if (event)
server->event = sd_event_ref(event);
else {
r = sd_event_default(&server->event);
if (r < 0)
return r;
}
server->event_priority = priority;
return 0;
}
int sd_dhcp_server_detach_event(sd_dhcp_server *server) {
assert_return(server, -EINVAL);
server->event = sd_event_unref(server->event);
return 0;
}
sd_event *sd_dhcp_server_get_event(sd_dhcp_server *server) {
assert_return(server, NULL);
return server->event;
}
int sd_dhcp_server_stop(sd_dhcp_server *server) {
assert_return(server, -EINVAL);
server->receive_message =
sd_event_source_unref(server->receive_message);
server->fd = safe_close(server->fd);
log_dhcp_server(server, "STOPPED");
return 0;
}
static int server_receive_message(sd_event_source *s, int fd,
uint32_t revents, void *userdata) {
_cleanup_free_ uint8_t *message = NULL;
uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))];
sd_dhcp_server *server = userdata;
struct iovec iov = {};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cmsgbuf,
.msg_controllen = sizeof(cmsgbuf),
};
struct cmsghdr *cmsg;
int buflen = 0, len, r;
assert(server);
r = ioctl(fd, FIONREAD, &buflen);
if (r < 0)
return r;
if (buflen < 0)
return -EIO;
message = malloc0(buflen);
if (!message)
return -ENOMEM;
iov.iov_base = message;
iov.iov_len = buflen;
len = recvmsg(fd, &msg, 0);
if (len < buflen)
return 0;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IP &&
cmsg->cmsg_type == IP_PKTINFO &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) {
struct in_pktinfo *info = (struct in_pktinfo*)CMSG_DATA(cmsg);
/* TODO figure out if this can be done as a filter on the socket, like for IPv6 */
if (server->index != info->ipi_ifindex)
return 0;
break;
}
}
log_dhcp_server(server, "received message");
return 1;
}
int sd_dhcp_server_start(sd_dhcp_server *server) {
int r;
assert_return(server, -EINVAL);
assert_return(server->event, -EINVAL);
assert_return(!server->receive_message, -EBUSY);
assert_return(server->fd == -1, -EBUSY);
r = dhcp_network_bind_udp_socket(INADDR_ANY, DHCP_PORT_SERVER);
if (r < 0) {
sd_dhcp_server_stop(server);
return r;
}
server->fd = r;
r = sd_event_add_io(server->event, &server->receive_message,
server->fd, EPOLLIN,
server_receive_message, server);
if (r < 0) {
sd_dhcp_server_stop(server);
return r;
}
r = sd_event_source_set_priority(server->receive_message,
server->event_priority);
if (r < 0) {
sd_dhcp_server_stop(server);
return r;
}
log_dhcp_server(server, "STARTED");
return 0;
}
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