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Wire up the netlink socket to the epoll handler. Still need to actually

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react to events in the processing function.
Pass the client_state structure to the netlink code explicitly rather than
making it a global variable.
This commit is contained in:
Nicholas J. Kain 2011-03-29 15:34:00 -04:00
parent 55bc002ad6
commit 9d03795a15
5 changed files with 100 additions and 46 deletions
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11
ndhc/config.h
View File

@ -24,13 +24,22 @@ enum {
LM_RAW
};
enum {
IFS_NONE = 0,
IFS_UP,
IFS_DOWN,
IFS_SHUT,
IFS_REMOVED
};
struct client_state_t {
unsigned long long leaseStartTime;
int dhcpState;
int arpPrevState;
int ifsPrevState;
int listenMode;
int packetNum;
int epollFd, signalFd, listenFd, arpFd;
int epollFd, signalFd, listenFd, arpFd, nlFd;
int timeout;
uint32_t requestedIP, serverAddr;
uint32_t lease, t1, t2, xid;

12
ndhc/ndhc.c
View File

@ -33,7 +33,6 @@
#include <signal.h>
#include <time.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/epoll.h>
#include <sys/signalfd.h>
#include <net/if.h>
@ -67,6 +66,7 @@
struct client_state_t cs = {
.dhcpState = DS_INIT_SELECTING,
.arpPrevState = DS_NULL,
.ifsPrevState = IFS_NONE,
.listenMode = LM_NONE,
.packetNum = 0,
.xid = 0,
@ -81,6 +81,7 @@ struct client_state_t cs = {
.signalFd = -1,
.listenFd = -1,
.arpFd = -1,
.nlFd = -1,
};
struct client_config_t client_config = {
@ -223,6 +224,7 @@ static void do_work(void)
if (cs.epollFd == -1)
suicide("epoll_create1 failed");
setup_signals(&cs);
epoll_add(&cs, cs.nlFd);
change_listen_mode(&cs, LM_RAW);
handle_timeout(&cs);
@ -243,6 +245,8 @@ static void do_work(void)
handle_packet(&cs);
else if (fd == cs.arpFd)
handle_arp_response(&cs);
else if (fd == cs.nlFd)
handle_nl_message(&cs);
else
suicide("epoll_wait: unknown fd");
}
@ -363,11 +367,11 @@ int main(int argc, char **argv)
write_pid(pidfile);
}
if (nl_open() < 0) {
if (nl_open(&cs) < 0) {
log_line("FATAL - failed to open netlink socket");
exit(EXIT_FAILURE);
}
if (nl_getifdata(client_config.interface) < 0) {
if (nl_getifdata(client_config.interface, &cs) < 0) {
log_line("FATAL - failed to get interface MAC and index");
exit(EXIT_FAILURE);
}
@ -398,6 +402,6 @@ int main(int argc, char **argv)
do_work();
nl_close();
nl_close(&cs);
return EXIT_SUCCESS;
}

111
ndhc/netlink.c
View File

@ -17,23 +17,17 @@
#include <unistd.h>
#include <net/if.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <sys/select.h>
#include <fcntl.h>
#include "netlink.h"
#include "config.h"
#include "log.h"
// OS_REMOVED -> exit
// OS_SHUT -> exit
// OS_DOWN -> action
// OS_UP -> action
#define NLMSG_RECVSIZE 8192
static int nl_socket = -1;
static unsigned int nl_seq;
/* internal callback handling */
@ -43,7 +37,8 @@ static __u32 nlcb_pid;
static unsigned int nlcb_seq;
static char nlcb_run;
int nl_open() {
int nl_open(struct client_state_t *cs)
{
struct sockaddr_nl nlsock = {
.nl_family = AF_NETLINK,
.nl_pad = 0,
@ -53,37 +48,40 @@ int nl_open() {
nlcb_pid = nlsock.nl_pid;
assert(nl_socket == -1);
assert(cs->nlFd == -1);
nl_socket = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
cs->nlFd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (nl_socket == -1) return -1;
if (cs->nlFd == -1)
return -1;
if (bind(nl_socket, (const struct sockaddr *)&nlsock, sizeof(nlsock)))
if (bind(cs->nlFd, (const struct sockaddr *)&nlsock, sizeof(nlsock)))
goto err_close;
if (fcntl(nl_socket, F_SETFD, FD_CLOEXEC))
if (fcntl(cs->nlFd, F_SETFD, FD_CLOEXEC))
goto err_close;
return 0;
err_close:
nl_close();
nl_close(cs);
return -1;
}
void nl_close() {
close(nl_socket);
nl_socket = -1;
void nl_close(struct client_state_t *cs)
{
close(cs->nlFd);
cs->nlFd = -1;
}
void nl_queryifstatus(int ifidx) {
void nl_queryifstatus(int ifidx, struct client_state_t *cs)
{
struct {
struct nlmsghdr hdr;
struct ifinfomsg ifinfo;
} req;
req.hdr.nlmsg_len = sizeof(req);
req.hdr.nlmsg_len = sizeof req;
req.hdr.nlmsg_type = RTM_GETLINK;
req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
req.hdr.nlmsg_seq = ++nl_seq;
@ -93,11 +91,13 @@ void nl_queryifstatus(int ifidx) {
req.ifinfo.ifi_flags = IFF_UP;
req.ifinfo.ifi_change = 0xffffffff;
send(nl_socket, &req, sizeof(req),0);
send(cs->nlFd, &req, sizeof req, 0);
}
static void nl_handlemsg(struct nlmsghdr *msg, unsigned int len) {
// Decode netlink messages and process them
static void nl_handlemsg(struct nlmsghdr *msg, unsigned int len,
struct client_state_t *cs)
{
if (len < sizeof(*msg)) return;
while(NLMSG_OK(msg,len)) {
@ -118,17 +118,41 @@ static void nl_handlemsg(struct nlmsghdr *msg, unsigned int len) {
if (ifinfo->ifi_index != client_config.ifindex)
break;
if (ifinfo->ifi_flags & IFF_UP) {
if (ifinfo->ifi_flags & IFF_RUNNING)
printf("XXX_OS_UP() NYI\n");
else
printf("XXX_OS_DOWN() NYI\n");
} else
printf("XXX_OS_SHUT() NYI\n");
if (ifinfo->ifi_flags & IFF_RUNNING) {
if (cs->ifsPrevState != IFS_UP) {
cs->ifsPrevState = IFS_UP;
/*
* If we have a lease, then check to see
* if our gateway is still valid. If it fails,
* state -> INIT_REBOOT.
*
* If we don't have a lease, state -> INIT.
*/
}
} else {
if (cs->ifsPrevState != IFS_DOWN) {
cs->ifsPrevState = IFS_DOWN;
/*
* state -> DOWN
*/
}
}
} else {
if (cs->ifsPrevState != IFS_SHUT) {
cs->ifsPrevState = IFS_SHUT;
log_line("Interface shut down; exiting.");
exit(EXIT_SUCCESS);
}
}
break;
case RTM_DELLINK:
if (ifinfo->ifi_index != client_config.ifindex)
break;
printf("XXX_OS_REMOVED() NYI\n");
if (cs->ifsPrevState != IFS_REMOVED) {
cs->ifsPrevState = IFS_REMOVED;
log_line("Interface removed; exiting.");
exit(EXIT_SUCCESS);
}
break;
default:
break;
@ -138,21 +162,35 @@ static void nl_handlemsg(struct nlmsghdr *msg, unsigned int len) {
}
}
static void nl_sync_dump() {
void handle_nl_message(struct client_state_t *cs)
{
char c[NLMSG_RECVSIZE];
struct nlmsghdr *msg = (struct nlmsghdr *)c;
int n;
assert(cs->nlFd != -1);
n = recv(cs->nlFd, c, NLMSG_RECVSIZE, 0);
nl_handlemsg(msg, n, cs);
}
// Wait for and synchronously process netlink replies until a callback completes
static void nl_sync_dump(struct client_state_t *cs)
{
char c[NLMSG_RECVSIZE];
struct nlmsghdr *msg = (struct nlmsghdr *)c;
int n;
nlcb_seq = nl_seq;
for(nlcb_run = 1; nlcb_run;) {
n = recv(nl_socket, c, NLMSG_RECVSIZE, 0);
n = recv(cs->nlFd, c, NLMSG_RECVSIZE, 0);
assert(n >= 0);
nl_handlemsg(msg,n);
nl_handlemsg(msg, n, cs);
}
}
// Callback function for getting interface mac address and index.
static void copy_ifdata(struct nlmsghdr *msg, void **args) {
static void copy_ifdata(struct nlmsghdr *msg, void **args)
{
struct ifinfomsg *ifinfo = NLMSG_DATA(msg);
struct rtattr *rta = IFLA_RTA(ifinfo);
int len = NLMSG_PAYLOAD(msg, sizeof(*ifinfo));
@ -193,7 +231,8 @@ static void copy_ifdata(struct nlmsghdr *msg, void **args) {
}
// Gets interface mac address and index (synchronous).
int nl_getifdata(const char *ifname) {
int nl_getifdata(const char *ifname, struct client_state_t *cs)
{
struct {
struct nlmsghdr hdr;
struct ifinfomsg ifinfo;
@ -206,12 +245,12 @@ int nl_getifdata(const char *ifname) {
req.hdr.nlmsg_pid = nlcb_pid;
req.ifinfo.ifi_family = AF_UNSPEC;
if (send(nl_socket, &req, sizeof(req), 0) != sizeof(req)) return -1;
if (send(cs->nlFd, &req, sizeof(req), 0) != sizeof(req)) return -1;
nlcb_function = copy_ifdata;
nlcb_args[0] = NULL;
nl_sync_dump();
nl_sync_dump(cs);
return nlcb_args[0]?0:-1;
}

11
ndhc/netlink.h
View File

@ -1,9 +1,12 @@
#ifndef NK_NETLINK_H_
#define NK_NETLINK_H_
int nl_open();
void nl_close();
void nl_queryifstatus(int ifidx);
int nl_getifdata(const char *ifname);
#include "config.h"
int nl_open(struct client_state_t *cs);
void nl_close(struct client_state_t *cs);
void nl_queryifstatus(int ifidx, struct client_state_t *cs);
void handle_nl_message(struct client_state_t *cs);
int nl_getifdata(const char *ifname, struct client_state_t *cs);
#endif /* NK_NETLINK_H_ */

1
ndhc/socket.c
View File

@ -23,7 +23,6 @@
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <unistd.h>
#include <fcntl.h>