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enabled gratuitous arp packets (#474)

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Co-authored-by: Logan007 <you@example.com>
This commit is contained in:
Logan oos Even 2020-11-09 16:04:41 +01:00 committed by GitHub
parent a2db28275c
commit 6da8e5497e
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3 changed files with 58 additions and 56 deletions
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53
src/edge.c
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@ -664,59 +664,6 @@ static int loadFromFile(const char *path, n2n_edge_conf_t *conf, n2n_tuntap_priv
/* ************************************** */
#if defined(DUMMY_ID_00001) /* Disabled waiting for config option to enable it */
static char gratuitous_arp[] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* Dest mac */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Src mac */
0x08, 0x06, /* ARP */
0x00, 0x01, /* Ethernet */
0x08, 0x00, /* IP */
0x06, /* Hw Size */
0x04, /* Protocol Size */
0x00, 0x01, /* ARP Request */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Src mac */
0x00, 0x00, 0x00, 0x00, /* Src IP */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Target mac */
0x00, 0x00, 0x00, 0x00 /* Target IP */
};
/* ************************************** */
/** Build a gratuitous ARP packet for a /24 layer 3 (IP) network. */
static int build_gratuitous_arp(char *buffer, uint16_t buffer_len) {
if(buffer_len < sizeof(gratuitous_arp)) return(-1);
memcpy(buffer, gratuitous_arp, sizeof(gratuitous_arp));
memcpy(&buffer[6], device.mac_addr, 6);
memcpy(&buffer[22], device.mac_addr, 6);
memcpy(&buffer[28], &device.ip_addr, 4);
/* REVISIT: BbMaj7 - use a real netmask here. This is valid only by accident
* for /24 IPv4 networks. */
buffer[31] = 0xFF; /* Use a faked broadcast address */
memcpy(&buffer[38], &device.ip_addr, 4);
return(sizeof(gratuitous_arp));
}
/* ************************************** */
/** Called from update_supernode_reg to periodically send gratuitous ARP
* broadcasts. */
static void send_grat_arps(n2n_edge_t * eee,) {
char buffer[48];
size_t len;
traceEvent(TRACE_NORMAL, "Sending gratuitous ARP...");
len = build_gratuitous_arp(buffer, sizeof(buffer));
send_packet2net(eee, buffer, len);
send_packet2net(eee, buffer, len); /* Two is better than one :-) */
}
#endif /* #if defined(DUMMY_ID_00001) */
/* ************************************** */
static void daemonize() {
#ifndef WIN32
int childpid;

46
src/edge_utils.c
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@ -929,6 +929,49 @@ static void send_register_ack(n2n_edge_t * eee,
/* ************************************** */
static char gratuitous_arp[] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* dest MAC */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* src MAC */
0x08, 0x06, /* ARP */
0x00, 0x01, /* ethernet */
0x08, 0x00, /* IP */
0x06, /* hw Size */
0x04, /* protocol Size */
0x00, 0x02, /* ARP reply */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* src MAC */
0x00, 0x00, 0x00, 0x00, /* src IP */
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* target MAC */
0x00, 0x00, 0x00, 0x00 /* target IP */
};
// build a gratuitous ARP packet */
static int build_gratuitous_arp(n2n_edge_t * eee, char *buffer, uint16_t buffer_len) {
if(buffer_len < sizeof(gratuitous_arp)) return(-1);
memcpy(buffer, gratuitous_arp, sizeof(gratuitous_arp));
memcpy(&buffer[6], eee->device.mac_addr, 6);
memcpy(&buffer[22], eee->device.mac_addr, 6);
memcpy(&buffer[28], &(eee->device.ip_addr), 4);
memcpy(&buffer[38], &(eee->device.ip_addr), 4);
return(sizeof(gratuitous_arp));
}
/** Called from update_supernode_reg to periodically send gratuitous ARP
* broadcasts. */
static void send_grat_arps(n2n_edge_t * eee) {
char buffer[48];
size_t len;
traceEvent(TRACE_DEBUG, "Sending gratuitous ARP...");
len = build_gratuitous_arp(eee, buffer, sizeof(buffer));
edge_send_packet2net(eee, buffer, len);
edge_send_packet2net(eee, buffer, len); /* Two is better than one :-) */
}
/* ************************************** */
/** @brief Check to see if we should re-register with the supernode.
*
* This is frequently called by the main loop.
@ -982,8 +1025,7 @@ void update_supernode_reg(n2n_edge_t * eee, time_t nowTime) {
eee->sn_wait=1;
/* REVISIT: turn-on gratuitous ARP with config option. */
/* send_grat_arps(sock_fd, is_udp_sock); */
send_grat_arps(eee);
eee->last_register_req = nowTime;
}

15
src/sn_utils.c
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@ -323,7 +323,7 @@ static int update_edge(n2n_sn_t *sss,
time_t now) {
macstr_t mac_buf;
n2n_sock_str_t sockbuf;
struct peer_info *scan;
struct peer_info *scan, *iter, *tmp;
traceEvent(TRACE_DEBUG, "update_edge for %s [%s]",
macaddr_str(mac_buf, reg->edgeMac),
@ -331,6 +331,19 @@ static int update_edge(n2n_sn_t *sss,
HASH_FIND_PEER(comm->edges, reg->edgeMac, scan);
// if unknown, make sure it is also not known by IP address
if (NULL == scan) {
HASH_ITER(hh,comm->edges,iter,tmp) {
if(iter->dev_addr.net_addr == reg->dev_addr.net_addr) {
scan = iter;
HASH_DEL(comm->edges, scan);
memcpy(&(scan->mac_addr), reg->edgeMac, sizeof(n2n_mac_t));
HASH_ADD_PEER(comm->edges, scan);
break;
}
}
}
if (NULL == scan) {
/* Not known */