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#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <time.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <net/ethernet.h>
#include <netinet/ip.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if_arp.h>
#include <linux/if_packet.h>
#include "list.h"
#include "triton.h"
#include "log.h"
#include "ipoe.h"
#include "memdebug.h"
struct _arphdr {
__be16 ar_hrd;
__be16 ar_pro;
__u8 ar_hln;
__u8 ar_pln;
__be16 ar_op;
__u8 ar_sha[ETH_ALEN];
__be32 ar_spa;
__u8 ar_tha[ETH_ALEN];
__be32 ar_tpa;
} __packed;
static int arp_read(struct triton_md_handler_t *h)
{
struct arp_serv *s = container_of(h, typeof(*s), h);
char buf[128];
int n;
struct _arphdr *ah = (struct _arphdr *)buf;
struct _arphdr ah2;
struct sockaddr_ll src, dst;
socklen_t slen = sizeof(src);
struct ipoe_session *ses, *ses1, *ses2;
memset(&dst, 0, sizeof(dst));
dst.sll_family = AF_PACKET;
dst.sll_ifindex = s->ipoe->ifindex;
dst.sll_protocol = htons(ETH_P_ARP);
ah2.ar_hrd = htons(ARPHRD_ETHER);
ah2.ar_pro = htons(ETH_P_IP);
ah2.ar_hln = ETH_ALEN;
ah2.ar_pln = 4;
ah2.ar_op = htons(ARPOP_REPLY);
while (1) {
n = recvfrom(h->fd, buf, sizeof(buf), MSG_DONTWAIT, (struct sockaddr *)&src, &slen);
if (n < 0) {
if (errno == EAGAIN)
break;
continue;
}
if (n < sizeof(*ah))
continue;
if (ah->ar_op != htons(ARPOP_REQUEST))
continue;
if (ah->ar_pln != 4)
continue;
if (ah->ar_pro != htons(ETH_P_IP))
continue;
if (ah->ar_hln != ETH_ALEN)
continue;
if (memcmp(ah->ar_sha, src.sll_addr, ETH_ALEN))
continue;
ses1 = ses2 = NULL;
pthread_mutex_lock(&s->ipoe->lock);
list_for_each_entry(ses, &s->ipoe->sessions, entry) {
if (ses->yiaddr == ah->ar_spa) {
ses1 = ses;
if (ses->ses.state != AP_STATE_ACTIVE)
break;
}
if (ses->yiaddr == ah->ar_tpa) {
ses2 = ses;
if (ses->ses.state != AP_STATE_ACTIVE)
break;
}
if (ses1 && ses2)
break;
}
if (!ses1 || (ses1->ses.state != AP_STATE_ACTIVE) ||
(ses2 && ses2->ses.state != AP_STATE_ACTIVE)) {
pthread_mutex_unlock(&s->ipoe->lock);
continue;
}
if (ses2) {
if (s->ipoe->opt_arp == 1 || ses1 == ses2) {
pthread_mutex_unlock(&s->ipoe->lock);
continue;
}
if (s->ipoe->opt_arp == 2)
memcpy(ah2.ar_sha, ses2->hwaddr, ETH_ALEN);
else
memcpy(ah2.ar_sha, s->ipoe->hwaddr, ETH_ALEN);
} else
memcpy(ah2.ar_sha, s->ipoe->hwaddr, ETH_ALEN);
pthread_mutex_unlock(&s->ipoe->lock);
memcpy(dst.sll_addr, ah->ar_sha, ETH_ALEN);
memcpy(ah2.ar_tha, ah->ar_sha, ETH_ALEN);
ah2.ar_spa = ah->ar_tpa;
ah2.ar_tpa = ah->ar_spa;
sendto(h->fd, &ah2, sizeof(ah2), MSG_DONTWAIT, (struct sockaddr *)&dst, sizeof(dst));
}
return 0;
}
struct arp_serv *arpd_start(struct ipoe_serv *ipoe)
{
int sock;
struct sockaddr_ll addr;
struct arp_serv *s;
int f = 1, fd;
char fname[1024];
sprintf(fname, "/proc/sys/net/ipv4/conf/%s/proxy_arp", ipoe->ifname);
fd = open(fname, O_WRONLY);
if (fd >= 0) {
fname[0] = '0';
write(fd, fname, 1);
close(fd);
}
sock = socket(PF_PACKET, SOCK_DGRAM, 0);
if (sock < 0) {
log_error("ipoe: arp: socket: %s\n", strerror(errno));
return NULL;
}
memset(&addr, 0, sizeof(addr));
addr.sll_family = AF_PACKET;
addr.sll_protocol = htons(ETH_P_ARP);
addr.sll_ifindex = ipoe->ifindex;
if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &f, sizeof(f))) {
log_error("ipoe: setsockopt(SO_BROADCAST): %s\n", strerror(errno));
close(sock);
return NULL;
}
if (bind(sock, (struct sockaddr *)&addr, sizeof(addr))) {
log_error("ipoe: arp: bind: %s\n", strerror(errno));
close(sock);
return NULL;
}
s = _malloc(sizeof(*s));
s->ipoe = ipoe;
s->h.fd = sock;
s->h.read = arp_read;
fcntl(sock, F_SETFL, O_NONBLOCK);
fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC);
triton_md_register_handler(&ipoe->ctx, &s->h);
triton_md_enable_handler(&s->h, MD_MODE_READ);
return s;
}
void arpd_stop(struct arp_serv *arp)
{
triton_md_unregister_handler(&arp->h, 1);
_free(arp);
}
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