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l2tpns/cluster.c

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// L2TPNS Clustering Stuff
char const *cvs_id_cluster = "$Id: cluster.c,v 1.37 2005-05-08 08:00:49 bodea Exp $";
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <inttypes.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <string.h>
#include <malloc.h>
#include <errno.h>
#include <libcli.h>
#include "l2tpns.h"
#include "cluster.h"
#include "util.h"
#include "tbf.h"
#ifdef BGP
#include "bgp.h"
#endif
/*
* All cluster packets have the same format.
*
* One or more instances of
* a 32 bit 'type' id.
* a 32 bit 'extra' data dependant on the 'type'.
* zero or more bytes of structure data, dependant on the type.
*
*/
// Module variables.
int cluster_sockfd = 0; // The filedescriptor for the cluster communications port.
in_addr_t my_address = 0; // The network address of my ethernet port.
static int walk_session_number = 0; // The next session to send when doing the slow table walk.
static int walk_tunnel_number = 0; // The next tunnel to send when doing the slow table walk.
int forked = 0; // Sanity check: CLI must not diddle with heartbeat table
#define MAX_HEART_SIZE (8192) // Maximum size of heartbeat packet. Must be less than max IP packet size :)
#define MAX_CHANGES (MAX_HEART_SIZE/(sizeof(sessiont) + sizeof(int) ) - 2) // Assumes a session is the biggest type!
static struct {
int type;
int id;
} cluster_changes[MAX_CHANGES]; // Queue of changed structures that need to go out when next heartbeat.
static struct {
int seq;
int size;
char data[MAX_HEART_SIZE];
} past_hearts[HB_HISTORY_SIZE]; // Ring buffer of heartbeats that we've recently sent out. Needed so
// we can re-transmit if needed.
static struct {
in_addr_t peer;
uint32_t basetime;
clockt timestamp;
int uptodate;
} peers[CLUSTER_MAX_SIZE]; // List of all the peers we've heard from.
static int num_peers; // Number of peers in list.
static int rle_decompress(uint8_t **src_p, int ssize, uint8_t *dst, int dsize);
static int rle_compress(uint8_t **src_p, int ssize, uint8_t *dst, int dsize);
//
// Create a listening socket
//
// This joins the cluster multi-cast group.
//
int cluster_init()
{
struct sockaddr_in addr;
struct sockaddr_in interface_addr;
struct ip_mreq mreq;
struct ifreq ifr;
int opt;
config->cluster_undefined_sessions = MAXSESSION-1;
config->cluster_undefined_tunnels = MAXTUNNEL-1;
if (!config->cluster_address)
return 0;
if (!*config->cluster_interface)
return 0;
cluster_sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(CLUSTERPORT);
addr.sin_addr.s_addr = INADDR_ANY;
setsockopt(cluster_sockfd, SOL_SOCKET, SO_REUSEADDR, &addr, sizeof(addr));
opt = fcntl(cluster_sockfd, F_GETFL, 0);
fcntl(cluster_sockfd, F_SETFL, opt | O_NONBLOCK);
if (bind(cluster_sockfd, (void *) &addr, sizeof(addr)) < 0)
{
LOG(0, 0, 0, "Failed to bind cluster socket: %s\n", strerror(errno));
return -1;
}
strcpy(ifr.ifr_name, config->cluster_interface);
if (ioctl(cluster_sockfd, SIOCGIFADDR, &ifr) < 0)
{
LOG(0, 0, 0, "Failed to get interface address for (%s): %s\n", config->cluster_interface, strerror(errno));
return -1;
}
memcpy(&interface_addr, &ifr.ifr_addr, sizeof(interface_addr));
my_address = interface_addr.sin_addr.s_addr;
// Join multicast group.
mreq.imr_multiaddr.s_addr = config->cluster_address;
mreq.imr_interface = interface_addr.sin_addr;
opt = 0; // Turn off multicast loopback.
setsockopt(cluster_sockfd, IPPROTO_IP, IP_MULTICAST_LOOP, &opt, sizeof(opt));
if (setsockopt(cluster_sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
{
LOG(0, 0, 0, "Failed to setsockopt (join mcast group): %s\n", strerror(errno));
return -1;
}
if (setsockopt(cluster_sockfd, IPPROTO_IP, IP_MULTICAST_IF, &interface_addr, sizeof(interface_addr)) < 0)
{
LOG(0, 0, 0, "Failed to setsockopt (set mcast interface): %s\n", strerror(errno));
return -1;
}
config->cluster_last_hb = TIME;
config->cluster_seq_number = -1;
return cluster_sockfd;
}
//
// Send a chunk of data to the entire cluster (usually via the multicast
// address ).
//
static int cluster_send_data(void *data, int datalen)
{
struct sockaddr_in addr = {0};
if (!cluster_sockfd) return -1;
if (!config->cluster_address) return 0;
addr.sin_addr.s_addr = config->cluster_address;
addr.sin_port = htons(CLUSTERPORT);
addr.sin_family = AF_INET;
LOG(5, 0, 0, "Cluster send data: %d bytes\n", datalen);
if (sendto(cluster_sockfd, data, datalen, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0)
{
LOG(0, 0, 0, "sendto: %s\n", strerror(errno));
return -1;
}
return 0;
}
//
// Add a chunk of data to a heartbeat packet.
// Maintains the format. Assumes that the caller
// has passed in a big enough buffer!
//
static void add_type(char **p, int type, int more, char *data, int size)
{
*((uint32_t *) (*p)) = type;
*p += sizeof(uint32_t);
*((uint32_t *)(*p)) = more;
*p += sizeof(uint32_t);
if (data && size > 0) {
memcpy(*p, data, size);
*p += size;
}
}
// advertise our presence via BGP or gratuitous ARP
static void advertise(void)
{
#ifdef BGP
if (bgp_configured)
bgp_enable_routing(1);
else
#endif /* BGP */
if (config->send_garp)
send_garp(config->bind_address); // Start taking traffic.
}
static void cluster_uptodate(void)
{
if (config->cluster_iam_uptodate)
return;
if (config->cluster_undefined_sessions || config->cluster_undefined_tunnels)
return;
config->cluster_iam_uptodate = 1;
LOG(0, 0, 0, "Now uptodate with master.\n");
advertise();
}
//
// Send a unicast UDP packet to a peer with 'data' as the
// contents.
//
static int peer_send_data(in_addr_t peer, char *data, int size)
{
struct sockaddr_in addr = {0};
if (!cluster_sockfd) return -1;
if (!config->cluster_address) return 0;
if (!peer) // Odd??
return -1;
addr.sin_addr.s_addr = peer;
addr.sin_port = htons(CLUSTERPORT);
addr.sin_family = AF_INET;
LOG_HEX(5, "Peer send", data, size);
if (sendto(cluster_sockfd, data, size, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0)
{
LOG(0, 0, 0, "sendto: %s\n", strerror(errno));
return -1;
}
return 0;
}
//
// Send a structured message to a peer with a single element of type 'type'.
//
static int peer_send_message(in_addr_t peer, int type, int more, char *data, int size)
{
char buf[65536]; // Vast overkill.
char *p = buf;
LOG(4, 0, 0, "Sending message to peer (type %d, more %d, size %d)\n", type, more, size);
add_type(&p, type, more, data, size);
return peer_send_data(peer, buf, (p-buf) );
}
//
// Forward a state changing packet to the master.
//
// The master just processes the payload as if it had
// received it off the tun device.
//
int master_forward_packet(char *data, int size, in_addr_t addr, int port)
{
char buf[65536]; // Vast overkill.
char *p = buf;
if (!config->cluster_master_address) // No election has been held yet. Just skip it.
return -1;
LOG(4, 0, 0, "Forwarding packet from %s to master (size %d)\n", fmtaddr(addr, 0), size);
STAT(c_forwarded);
add_type(&p, C_FORWARD, addr, (char *) &port, sizeof(port));
memcpy(p, data, size);
p += size;
return peer_send_data(config->cluster_master_address, buf, (p - buf));
}
//
// Forward a throttled packet to the master for handling.
//
// The master just drops the packet into the appropriate
// token bucket queue, and lets normal processing take care
// of it.
//
int master_throttle_packet(int tbfid, char *data, int size)
{
char buf[65536]; // Vast overkill.
char *p = buf;
if (!config->cluster_master_address) // No election has been held yet. Just skip it.
return -1;
LOG(4, 0, 0, "Throttling packet master (size %d, tbfid %d)\n", size, tbfid);
add_type(&p, C_THROTTLE, tbfid, data, size);
return peer_send_data(config->cluster_master_address, buf, (p-buf) );
}
//
// Forward a walled garden packet to the master for handling.
//
// The master just writes the packet straight to the tun
// device (where is will normally loop through the
// firewall rules, and come back in on the tun device)
//
// (Note that this must be called with the tun header
// as the start of the data).
int master_garden_packet(sessionidt s, char *data, int size)
{
char buf[65536]; // Vast overkill.
char *p = buf;
if (!config->cluster_master_address) // No election has been held yet. Just skip it.
return -1;
LOG(4, 0, 0, "Walled garden packet to master (size %d)\n", size);
add_type(&p, C_GARDEN, s, data, size);
return peer_send_data(config->cluster_master_address, buf, (p-buf));
}
//
// Send a chunk of data as a heartbeat..
// We save it in the history buffer as we do so.
//
static void send_heartbeat(int seq, char *data, int size)
{
int i;
if (size > sizeof(past_hearts[0].data))
{
LOG(0, 0, 0, "Tried to heartbeat something larger than the maximum packet!\n");
kill(0, SIGTERM);
exit(1);
}
i = seq % HB_HISTORY_SIZE;
past_hearts[i].seq = seq;
past_hearts[i].size = size;
memcpy(&past_hearts[i].data, data, size); // Save it.
cluster_send_data(data, size);
}
//
// Send an 'i am alive' message to every machine in the cluster.
//
void cluster_send_ping(time_t basetime)
{
char buff[100 + sizeof(pingt)];
char *p = buff;
pingt x;
if (config->cluster_iam_master && basetime) // We're heartbeating so no need to ping.
return;
LOG(5, 0, 0, "Sending cluster ping...\n");
x.ver = 1;
x.addr = config->bind_address;
x.undef = config->cluster_undefined_sessions + config->cluster_undefined_tunnels;
x.basetime = basetime;
add_type(&p, C_PING, basetime, (char *) &x, sizeof(x));
cluster_send_data(buff, (p-buff) );
}
//
// Walk the session counters looking for non-zero ones to send
// to the master. We send up to 600 of them at one time.
// We examine a maximum of 3000 sessions.
// (50k max session should mean that we normally
// examine the entire session table every 25 seconds).
#define MAX_B_RECS (600)
void master_update_counts(void)
{
int i, c;
bytest b[MAX_B_RECS+1];
if (config->cluster_iam_master) // Only happens on the slaves.
return;
if (!config->cluster_master_address) // If we don't have a master, skip it for a while.
return;
i = MAX_B_RECS * 5; // Examine max 2000 sessions;
if (config->cluster_highest_sessionid > i)
i = config->cluster_highest_sessionid;
for ( c = 0; i > 0 ; --i) {
// Next session to look at.
walk_session_number++;
if ( walk_session_number > config->cluster_highest_sessionid)
walk_session_number = 1;
if (!sess_local[walk_session_number].cin && !sess_local[walk_session_number].cout)
continue; // Unused. Skip it.
b[c].sid = walk_session_number;
b[c].in = sess_local[walk_session_number].cin;
b[c].out = sess_local[walk_session_number].cout;
if (++c > MAX_B_RECS) // Send a max of 400 elements in a packet.
break;
// Reset counters.
sess_local[walk_session_number].cin = sess_local[walk_session_number].cout = 0;
}
if (!c) // Didn't find any that changes. Get out of here!
return;
// Forward the data to the master.
LOG(4, 0, 0, "Sending byte counters to master (%d elements)\n", c);
peer_send_message(config->cluster_master_address, C_BYTES, c, (char *) &b, sizeof(b[0]) * c);
return;
}
//
// On the master, check how our slaves are going. If
// one of them's not up-to-date we'll heartbeat faster.
// If we don't have any of them, then we need to turn
// on our own packet handling!
//
void cluster_check_slaves(void)
{
int i;
static int have_peers = 0;
int had_peers = have_peers;
clockt t = TIME;
if (!config->cluster_iam_master)
return; // Only runs on the master...
config->cluster_iam_uptodate = 1; // cleared in loop below
for (i = have_peers = 0; i < num_peers; i++)
{
if ((peers[i].timestamp + config->cluster_hb_timeout) < t)
continue; // Stale peer! Skip them.
if (!peers[i].basetime)
continue; // Shutdown peer! Skip them.
if (peers[i].uptodate)
have_peers = 1;
if (!peers[i].uptodate)
config->cluster_iam_uptodate = 0; // Start fast heartbeats
}
#ifdef BGP
// in a cluster, withdraw/add routes when we get a peer/lose all peers
if (bgp_configured && have_peers != had_peers)
bgp_enable_routing(!have_peers);
#endif /* BGP */
}
//
// Check that we have a master. If it's been too
// long since we heard from a master then hold an election.
//
void cluster_check_master(void)
{
int i, count, tcount, high_unique_id = 0;
int last_free = 0;
clockt t = TIME;
static int probed = 0;
if (config->cluster_iam_master)
return; // Only runs on the slaves...
// If the master is late (missed 2 hearbeats by a second and a
// hair) it may be that the switch has dropped us from the
// multicast group, try unicasting one probe to the master
// which will hopefully respond with a unicast heartbeat that
// will allow us to limp along until the querier next runs.
if (TIME > (config->cluster_last_hb + 2 * config->cluster_hb_interval + 11))
{
if (!probed && config->cluster_master_address)
{
probed = 1;
LOG(1, 0, 0, "Heartbeat from master %.1fs late, probing...\n",
0.1 * (TIME - (config->cluster_last_hb + config->cluster_hb_interval)));
peer_send_message(config->cluster_master_address,
C_LASTSEEN, config->cluster_seq_number, NULL, 0);
}
} else { // We got a recent heartbeat; reset the probe flag.
probed = 0;
}
if (TIME < (config->cluster_last_hb + config->cluster_hb_timeout))
return; // Everything's ok!
config->cluster_last_hb = TIME + 1; // Just the one election thanks.
LOG(0, 0, 0, "Master timed out! Holding election...\n");
for (i = 0; i < num_peers; i++)
{
if ((peers[i].timestamp + config->cluster_hb_timeout) < t)
continue; // Stale peer! Skip them.
if (!peers[i].basetime)
continue; // Shutdown peer! Skip them.
if (peers[i].basetime < basetime) {
LOG(1, 0, 0, "Expecting %s to become master\n", fmtaddr(peers[i].peer, 0));
return; // They'll win the election. Get out of here.
}
if (peers[i].basetime == basetime &&
peers[i].peer > my_address) {
LOG(1, 0, 0, "Expecting %s to become master\n", fmtaddr(peers[i].peer, 0));
return; // They'll win the election. Wait for them to come up.
}
}
// Wow. it's been ages since I last heard a heartbeat
// and I'm better than an of my peers so it's time
// to become a master!!!
config->cluster_iam_master = 1;
config->cluster_master_address = 0;
LOG(0, 0, 0, "I am declaring myself the master!\n");
if (config->cluster_seq_number == -1)
config->cluster_seq_number = 0;
//
// Go through and mark all the tunnels as defined.
// Count the highest used tunnel number as well.
//
config->cluster_highest_tunnelid = 0;
for (i = 0, tcount = 0; i < MAXTUNNEL; ++i) {
if (tunnel[i].state == TUNNELUNDEF)
tunnel[i].state = TUNNELFREE;
if (tunnel[i].state != TUNNELFREE && i > config->cluster_highest_tunnelid)
config->cluster_highest_tunnelid = i;
}
//
// Go through and mark all the sessions as being defined.
// reset the idle timeouts.
// add temporary byte counters to permanent ones.
// Re-string the free list.
// Find the ID of the highest session.
last_free = 0;
high_unique_id = 0;
config->cluster_highest_sessionid = 0;
for (i = 0, count = 0; i < MAXSESSION; ++i) {
if (session[i].tunnel == T_UNDEF) {
session[i].tunnel = T_FREE;
++count;
}
if (!session[i].opened) { // Unused session. Add to free list.
memset(&session[i], 0, sizeof(session[i]));
session[i].tunnel = T_FREE;
session[last_free].next = i;
session[i].next = 0;
last_free = i;
continue;
}
// Reset idle timeouts..
session[i].last_packet = time_now;
// Reset die relative to our uptime rather than the old master's
if (session[i].die) session[i].die = TIME;
// Accumulate un-sent byte counters.
session[i].cin += sess_local[i].cin;
session[i].cout += sess_local[i].cout;
session[i].total_cin += sess_local[i].cin;
session[i].total_cout += sess_local[i].cout;
sess_local[i].cin = sess_local[i].cout = 0;
sess_local[i].radius = 0; // Reset authentication as the radius blocks aren't up to date.
if (session[i].unique_id >= high_unique_id) // This is different to the index into the session table!!!
high_unique_id = session[i].unique_id+1;
session[i].tbf_in = session[i].tbf_out = 0; // Remove stale pointers from old master.
throttle_session(i, session[i].throttle_in, session[i].throttle_out);
config->cluster_highest_sessionid = i;
}
session[last_free].next = 0; // End of chain.
last_id = high_unique_id; // Keep track of the highest used session ID.
become_master();
rebuild_address_pool();
// If we're not the very first master, this is a big issue!
if(count>0)
LOG(0, 0, 0, "Warning: Fixed %d uninitialized sessions in becoming master!\n", count);
config->cluster_undefined_sessions = 0;
config->cluster_undefined_tunnels = 0;
config->cluster_iam_uptodate = 1; // assume all peers are up-to-date
if (!num_peers) // lone master
advertise();
// FIXME. We need to fix up the tunnel control message
// queue here! There's a number of other variables we
// should also update.
}
//
// Check that our session table is validly matching what the
// master has in mind.
//
// In particular, if we have too many sessions marked 'undefined'
// we fix it up here, and we ensure that the 'first free session'
// pointer is valid.
//
static void cluster_check_sessions(int highsession, int freesession_ptr, int hightunnel)
{
int i;
sessionfree = freesession_ptr; // Keep the freesession ptr valid.
if (config->cluster_iam_uptodate)
return;
if (highsession > config->cluster_undefined_sessions && hightunnel > config->cluster_undefined_tunnels)
return;
// Clear out defined sessions, counting the number of
// undefs remaining.
config->cluster_undefined_sessions = 0;
for (i = 1 ; i < MAXSESSION; ++i) {
if (i > highsession) {
if (session[i].tunnel == T_UNDEF) session[i].tunnel = T_FREE; // Defined.
continue;
}
if (session[i].tunnel == T_UNDEF)
++config->cluster_undefined_sessions;
}
// Clear out defined tunnels, counting the number of
// undefs remaining.
config->cluster_undefined_tunnels = 0;
for (i = 1 ; i < MAXTUNNEL; ++i) {
if (i > hightunnel) {
if (tunnel[i].state == TUNNELUNDEF) tunnel[i].state = TUNNELFREE; // Defined.
continue;
}
if (tunnel[i].state == TUNNELUNDEF)
++config->cluster_undefined_tunnels;
}
if (config->cluster_undefined_sessions || config->cluster_undefined_tunnels) {
LOG(2, 0, 0, "Cleared undefined sessions/tunnels. %d sess (high %d), %d tunn (high %d)\n",
config->cluster_undefined_sessions, highsession, config->cluster_undefined_tunnels, hightunnel);
return;
}
// Are we up to date?
if (!config->cluster_iam_uptodate)
cluster_uptodate();
}
static int hb_add_type(char **p, int type, int id)
{
switch (type) {
case C_CSESSION: { // Compressed C_SESSION.
uint8_t c[sizeof(sessiont) * 2]; // Bigger than worst case.
uint8_t *d = (uint8_t *) &session[id];
uint8_t *orig = d;
int size;
size = rle_compress( &d, sizeof(sessiont), c, sizeof(c) );
// Did we compress the full structure, and is the size actually
// reduced??
if ( (d - orig) == sizeof(sessiont) && size < sizeof(sessiont) ) {
add_type(p, C_CSESSION, id, (char *) c, size);
break;
}
// Failed to compress : Fall through.
}
case C_SESSION: add_type(p, C_SESSION, id,
(char *) &session[id], sizeof(sessiont));
break;
case C_CTUNNEL: { // Compressed C_TUNNEL
uint8_t c[sizeof(tunnelt) * 2]; // Bigger than worst case.
uint8_t *d = (uint8_t *) &tunnel[id];
uint8_t *orig = d;
int size;
size = rle_compress( &d, sizeof(tunnelt), c, sizeof(c) );
// Did we compress the full structure, and is the size actually
// reduced??
if ( (d - orig) == sizeof(tunnelt) && size < sizeof(tunnelt) ) {
add_type(p, C_CTUNNEL, id, c, size);
break;
}
// Failed to compress : Fall through.
}
case C_TUNNEL: add_type(p, C_TUNNEL, id,
(char *) &tunnel[id], sizeof(tunnelt));
break;
default:
LOG(0, 0, 0, "Found an invalid type in heart queue! (%d)\n", type);
kill(0, SIGTERM);
exit(1);
}
return 0;
}
//
// Send a heartbeat, incidently sending out any queued changes..
//
void cluster_heartbeat()
{
int i, count = 0, tcount = 0;
char buff[MAX_HEART_SIZE + sizeof(heartt) + sizeof(int) ];
heartt h;
char *p = buff;
if (!config->cluster_iam_master) // Only the master does this.
return;
config->cluster_table_version += config->cluster_num_changes;
// Fill out the heartbeat header.
memset(&h, 0, sizeof(h));
h.version = HB_VERSION;
h.seq = config->cluster_seq_number;
h.basetime = basetime;
h.clusterid = config->bind_address; // Will this do??
h.basetime = basetime;
h.highsession = config->cluster_highest_sessionid;
h.freesession = sessionfree;
h.hightunnel = config->cluster_highest_tunnelid;
h.size_sess = sizeof(sessiont); // Just in case.
h.size_tunn = sizeof(tunnelt);
h.interval = config->cluster_hb_interval;
h.timeout = config->cluster_hb_timeout;
h.table_version = config->cluster_table_version;
add_type(&p, C_HEARTBEAT, HB_VERSION, (char *) &h, sizeof(h));
for (i = 0; i < config->cluster_num_changes; ++i) {
hb_add_type(&p, cluster_changes[i].type, cluster_changes[i].id);
}
if (p > (buff + sizeof(buff))) { // Did we somehow manage to overun the buffer?
LOG(0, 0, 0, "FATAL: Overran the heartbeat buffer! This is fatal. Exiting. (size %d)\n", (int) (p - buff));
kill(0, SIGTERM);
exit(1);
}
//
// Fill out the packet with sessions from the session table...
// (not forgetting to leave space so we can get some tunnels in too )
while ( (p + sizeof(uint32_t) * 2 + sizeof(sessiont) * 2 ) < (buff + MAX_HEART_SIZE) ) {
if (!walk_session_number) // session #0 isn't valid.
++walk_session_number;
if (count >= config->cluster_highest_sessionid) // If we're a small cluster, don't go wild.
break;
hb_add_type(&p, C_CSESSION, walk_session_number);
walk_session_number = (1+walk_session_number)%(config->cluster_highest_sessionid+1); // +1 avoids divide by zero.
++count; // Count the number of extra sessions we're sending.
}
//
// Fill out the packet with tunnels from the tunnel table...
// This effectively means we walk the tunnel table more quickly
// than the session table. This is good because stuffing up a
// tunnel is a much bigger deal than stuffing up a session.
//
while ( (p + sizeof(uint32_t) * 2 + sizeof(tunnelt) ) < (buff + MAX_HEART_SIZE) ) {
if (!walk_tunnel_number) // tunnel #0 isn't valid.
++walk_tunnel_number;
if (tcount >= config->cluster_highest_tunnelid)
break;
hb_add_type(&p, C_CTUNNEL, walk_tunnel_number);
walk_tunnel_number = (1+walk_tunnel_number)%(config->cluster_highest_tunnelid+1); // +1 avoids divide by zero.
++tcount;
}
//
// Did we do something wrong?
if (p > (buff + sizeof(buff))) { // Did we somehow manage to overun the buffer?
LOG(0, 0, 0, "Overran the heartbeat buffer now! This is fatal. Exiting. (size %d)\n", (int) (p - buff));
kill(0, SIGTERM);
exit(1);
}
LOG(3, 0, 0, "Sending v%d heartbeat #%d, change #%" PRIu64 " with %d changes "
"(%d x-sess, %d x-tunnels, %d highsess, %d hightun, size %d)\n",
HB_VERSION, h.seq, h.table_version, config->cluster_num_changes,
count, tcount, config->cluster_highest_sessionid,
config->cluster_highest_tunnelid, (int) (p - buff));
config->cluster_num_changes = 0;
send_heartbeat(h.seq, buff, (p-buff) ); // Send out the heartbeat to the cluster, keeping a copy of it.
config->cluster_seq_number = (config->cluster_seq_number+1)%HB_MAX_SEQ; // Next seq number to use.
}
//
// A structure of type 'type' has changed; Add it to the queue to send.
//
static int type_changed(int type, int id)
{
int i;
for (i = 0 ; i < config->cluster_num_changes ; ++i)
if ( cluster_changes[i].id == id &&
cluster_changes[i].type == type)
return 0; // Already marked for change.
cluster_changes[i].type = type;
cluster_changes[i].id = id;
++config->cluster_num_changes;
if (config->cluster_num_changes > MAX_CHANGES)
cluster_heartbeat(); // flush now
return 1;
}
// A particular session has been changed!
int cluster_send_session(int sid)
{
if (!config->cluster_iam_master) {
LOG(0, sid, 0, "I'm not a master, but I just tried to change a session!\n");
return -1;
}
if (forked) {
LOG(0, sid, 0, "cluster_send_session called from child process!\n");
return -1;
}
return type_changed(C_CSESSION, sid);
}
// A particular tunnel has been changed!
int cluster_send_tunnel(int tid)
{
if (!config->cluster_iam_master) {
LOG(0, 0, tid, "I'm not a master, but I just tried to change a tunnel!\n");
return -1;
}
return type_changed(C_CTUNNEL, tid);
}
//
// We're a master, and a slave has just told us that it's
// missed a packet. We'll resend it every packet since
// the last one it's seen.
//
static int cluster_catchup_slave(int seq, in_addr_t slave)
{
int s;
int diff;
LOG(1, 0, 0, "Slave %s sent LASTSEEN with seq %d\n", fmtaddr(slave, 0), seq);
diff = config->cluster_seq_number - seq; // How many packet do we need to send?
if (diff < 0)
diff += HB_MAX_SEQ;
if (diff >= HB_HISTORY_SIZE) { // Ouch. We don't have the packet to send it!
LOG(0, 0, 0, "A slave asked for message %d when our seq number is %d. Killing it.\n",
seq, config->cluster_seq_number);
return peer_send_message(slave, C_KILL, seq, NULL, 0);// Kill the slave. Nothing else to do.
}
// Now resend every packet that it missed, in order.
while (seq != config->cluster_seq_number) {
s = seq%HB_HISTORY_SIZE;
if (seq != past_hearts[s].seq) {
LOG(0, 0, 0, "Tried to re-send heartbeat for %s but %d doesn't match %d! (%d,%d)\n",
fmtaddr(slave, 0), seq, past_hearts[s].seq, s, config->cluster_seq_number);
return -1; // What to do here!?
}
peer_send_data(slave, past_hearts[s].data, past_hearts[s].size);
seq = (seq+1)%HB_MAX_SEQ; // Increment to next seq number.
}
return 0; // All good!
}
//
// We've heard from another peer! Add it to the list
// that we select from at election time.
//
static int cluster_add_peer(in_addr_t peer, time_t basetime, pingt *pp, int size)
{
int i;
in_addr_t clusterid;
pingt p;
// Allow for backward compatability.
// Just the ping packet into a new structure to allow
// for the possibility that we might have received
// more or fewer elements than we were expecting.
if (size > sizeof(p))
size = sizeof(p);
memset( (void *) &p, 0, sizeof(p) );
memcpy( (void *) &p, (void *) pp, size);
clusterid = p.addr;
if (clusterid != config->bind_address)
{
// Is this for us?
LOG(4, 0, 0, "Skipping ping from %s (different cluster)\n", fmtaddr(peer, 0));
return 0;
}
for (i = 0; i < num_peers ; ++i)
{
if (peers[i].peer != peer)
continue;
// This peer already exists. Just update the timestamp.
peers[i].basetime = basetime;
peers[i].timestamp = TIME;
peers[i].uptodate = !p.undef;
break;
}
// Is this the master shutting down??
if (peer == config->cluster_master_address && !basetime) {
LOG(3, 0, 0, "Master %s shutting down...\n", fmtaddr(config->cluster_master_address, 0));
config->cluster_master_address = 0;
config->cluster_last_hb = 0; // Force an election.
cluster_check_master();
return 0;
}
if (i >= num_peers)
{
LOG(4, 0, 0, "Adding %s as a peer\n", fmtaddr(peer, 0));
// Not found. Is there a stale slot to re-use?
for (i = 0; i < num_peers ; ++i)
{
if (!peers[i].basetime) // Shutdown
break;
if ((peers[i].timestamp + config->cluster_hb_timeout * 10) < TIME) // Stale.
break;
}
if (i >= CLUSTER_MAX_SIZE)
{
// Too many peers!!
LOG(0, 0, 0, "Tried to add %s as a peer, but I already have %d of them!\n", fmtaddr(peer, 0), i);
return -1;
}
peers[i].peer = peer;
peers[i].basetime = basetime;
peers[i].timestamp = TIME;
peers[i].uptodate = !p.undef;
if (i == num_peers)
++num_peers;
LOG(1, 0, 0, "Added %s as a new peer. Now %d peers\n", fmtaddr(peer, 0), num_peers);
}
return 1;
}
/* Handle the slave updating the byte counters for the master. */
//
// Note that we don't mark the session as dirty; We rely on
// the slow table walk to propogate this back out to the slaves.
//
static int cluster_handle_bytes(char *data, int size)
{
bytest *b;
b = (bytest *) data;
LOG(3, 0, 0, "Got byte counter update (size %d)\n", size);
/* Loop around, adding the byte
counts to each of the sessions. */
while (size >= sizeof(*b) ) {
if (b->sid > MAXSESSION) {
LOG(0, 0, 0, "Got C_BYTES with session #%d!\n", b->sid);
return -1; /* Abort processing */
}
session[b->sid].total_cin += b->in;
session[b->sid].total_cout += b->out;
session[b->sid].cin += b->in;
session[b->sid].cout += b->out;
if (b->in)
session[b->sid].last_packet = time_now; // Reset idle timer!
size -= sizeof(*b);
++b;
}
if (size != 0)
LOG(0, 0, 0, "Got C_BYTES with %d bytes of trailing junk!\n", size);
return size;
}
//
// Handle receiving a session structure in a heartbeat packet.
//
static int cluster_recv_session(int more, uint8_t *p)
{
if (more >= MAXSESSION) {
LOG(0, 0, 0, "DANGER: Received a heartbeat session id > MAXSESSION!\n");
return -1;
}
if (session[more].tunnel == T_UNDEF) {
if (config->cluster_iam_uptodate) { // Sanity.
LOG(0, 0, 0, "I thought I was uptodate but I just found an undefined session!\n");
} else {
--config->cluster_undefined_sessions;
}
}
load_session(more, (sessiont *) p); // Copy session into session table..
LOG(5, more, 0, "Received session update (%d undef)\n", config->cluster_undefined_sessions);
if (!config->cluster_iam_uptodate)
cluster_uptodate(); // Check to see if we're up to date.
return 0;
}
static int cluster_recv_tunnel(int more, uint8_t *p)
{
if (more >= MAXTUNNEL) {
LOG(0, 0, 0, "DANGER: Received a tunnel session id > MAXTUNNEL!\n");
return -1;
}
if (tunnel[more].state == TUNNELUNDEF) {
if (config->cluster_iam_uptodate) { // Sanity.
LOG(0, 0, 0, "I thought I was uptodate but I just found an undefined tunnel!\n");
} else {
--config->cluster_undefined_tunnels;
}
}
memcpy(&tunnel[more], p, sizeof(tunnel[more]) );
//
// Clear tunnel control messages. These are dynamically allocated.
// If we get unlucky, this may cause the tunnel to drop!
//
tunnel[more].controls = tunnel[more].controle = NULL;
tunnel[more].controlc = 0;
LOG(5, 0, more, "Received tunnel update\n");
if (!config->cluster_iam_uptodate)
cluster_uptodate(); // Check to see if we're up to date.
return 0;
}
// pre v5 heartbeat session structure
struct oldsession {
sessionidt next;
sessionidt far;
tunnelidt tunnel;
in_addr_t ip;
int ip_pool_index;
unsigned long unique_id;
uint16_t nr;
uint16_t ns;
uint32_t magic;
uint32_t cin, cout;
uint32_t pin, pout;
uint32_t total_cin;
uint32_t total_cout;
uint32_t id;
uint16_t throttle_in;
uint16_t throttle_out;
clockt opened;
clockt die;
time_t last_packet;
in_addr_t dns1, dns2;
routet route[MAXROUTE];
uint16_t radius;
uint16_t mru;
uint16_t tbf_in;
uint16_t tbf_out;
uint8_t l2tp_flags;
uint8_t reserved_old_snoop;
uint8_t walled_garden;
uint8_t flags1;
char random_vector[MAXTEL];
int random_vector_length;
char user[129];
char called[MAXTEL];
char calling[MAXTEL];
uint32_t tx_connect_speed;
uint32_t rx_connect_speed;
uint32_t flags;
in_addr_t snoop_ip;
uint16_t snoop_port;
uint16_t sid;
uint8_t filter_in;
uint8_t filter_out;
char reserved[18];
};
static uint8_t *convert_session(struct oldsession *old)
{
static sessiont new;
int i;
memset(&new, 0, sizeof(new));
new.next = old->next;
new.far = old->far;
new.tunnel = old->tunnel;
new.l2tp_flags = old->l2tp_flags;
new.flags = old->flags;
new.ip = old->ip;
new.ip_pool_index = old->ip_pool_index;
new.unique_id = old->unique_id;
new.nr = old->nr;
new.ns = old->ns;
new.magic = old->magic;
new.cin = old->cin;
new.cout = old->cout;
new.pin = old->pin;
new.pout = old->pout;
new.total_cin = old->total_cin;
new.total_cout = old->total_cout;
new.throttle_in = old->throttle_in;
new.throttle_out = old->throttle_out;
new.filter_in = old->filter_in;
new.filter_out = old->filter_out;
new.mru = old->mru;
new.opened = old->opened;
new.die = old->die;
new.last_packet = old->last_packet;
new.dns1 = old->dns1;
new.dns2 = old->dns2;
new.tbf_in = old->tbf_in;
new.tbf_out = old->tbf_out;
new.random_vector_length = old->random_vector_length;
new.tx_connect_speed = old->tx_connect_speed;
new.rx_connect_speed = old->rx_connect_speed;
new.snoop_ip = old->snoop_ip;
new.snoop_port = old->snoop_port;
new.walled_garden = old->walled_garden;
memcpy(new.random_vector, old->random_vector, sizeof(new.random_vector));
memcpy(new.user, old->user, sizeof(new.user));
memcpy(new.called, old->called, sizeof(new.called));
memcpy(new.calling, old->calling, sizeof(new.calling));
for (i = 0; i < MAXROUTE; i++)
memcpy(&new.route[i], &old->route[i], sizeof(new.route[i]));
return (uint8_t *) &new;
}
//
// Process a heartbeat..
//
// v3: added interval, timeout
// v4: added table_version
// v5: added ipv6, re-ordered session structure
static int cluster_process_heartbeat(uint8_t *data, int size, int more, uint8_t *p, in_addr_t addr)
{
heartt *h;
int s = size - (p-data);
int i, type;
int hb_ver = more;
#if HB_VERSION != 5
# error "need to update cluster_process_heartbeat()"
#endif
// we handle versions 3 through 5
if (hb_ver < 3 || hb_ver > HB_VERSION) {
LOG(0, 0, 0, "Received a heartbeat version that I don't support (%d)!\n", hb_ver);
return -1; // Ignore it??
}
// Ok. It's a heartbeat packet from a cluster master!
if (s < sizeof(*h))
goto shortpacket;
h = (heartt *) p;
p += sizeof(*h);
s -= sizeof(*h);
if (h->clusterid != config->bind_address)
return -1; // It's not part of our cluster.
if (config->cluster_iam_master) { // Sanity...
// Note that this MUST match the election process above!
LOG(0, 0, 0, "I just got a heartbeat from master %s, but _I_ am the master!\n", fmtaddr(addr, 0));
if (!h->basetime) {
LOG(0, 0, 0, "Heartbeat with zero basetime! Ignoring\n");
return -1; // Skip it.
}
if (hb_ver >= 4) {
if (h->table_version > config->cluster_table_version) {
LOG(0, 0, 0, "They've seen more state changes (%" PRIu64 " vs my %" PRIu64 ") so I'm gone!\n",
h->table_version, config->cluster_table_version);
kill(0, SIGTERM);
exit(1);
}
if (h->table_version < config->cluster_table_version)
return -1;
}
if (basetime > h->basetime) {
LOG(0, 0, 0, "They're an older master than me so I'm gone!\n");
kill(0, SIGTERM);
exit(1);
}
if (basetime < h->basetime)
return -1;
if (my_address < addr) { // Tie breaker.
LOG(0, 0, 0, "They're a higher IP address than me, so I'm gone!\n");
kill(0, SIGTERM);
exit(1);
}
return -1; // Skip it.
}
if (config->cluster_seq_number == -1) // Don't have one. Just align to the master...
config->cluster_seq_number = h->seq;
config->cluster_last_hb = TIME; // Reset to ensure that we don't become master!!
if (config->cluster_seq_number != h->seq) { // Out of sequence heartbeat!
static int lastseen_seq = 0;
static time_t lastseen_time = 0;
// limit to once per second for a particular seq#
int ask = (config->cluster_seq_number != lastseen_seq || time_now != lastseen_time);
LOG(1, 0, 0, "HB: Got seq# %d but was expecting %d. %s.\n",
h->seq, config->cluster_seq_number,
ask ? "Asking for resend" : "Ignoring");
if (ask)
{
lastseen_seq = config->cluster_seq_number;
lastseen_time = time_now;
peer_send_message(addr, C_LASTSEEN, config->cluster_seq_number, NULL, 0);
}
config->cluster_last_hb = TIME; // Reset to ensure that we don't become master!!
// Just drop the packet. The master will resend it as part of the catchup.
return 0;
}
// Save the packet in our buffer.
// This is needed in case we become the master.
config->cluster_seq_number = (h->seq+1)%HB_MAX_SEQ;
i = h->seq % HB_HISTORY_SIZE;
past_hearts[i].seq = h->seq;
past_hearts[i].size = size;
memcpy(&past_hearts[i].data, data, size); // Save it.
// Check that we don't have too many undefined sessions, and
// that the free session pointer is correct.
cluster_check_sessions(h->highsession, h->freesession, h->hightunnel);
if (h->interval != config->cluster_hb_interval)
{
LOG(2, 0, 0, "Master set ping/heartbeat interval to %u (was %u)\n",
h->interval, config->cluster_hb_interval);
config->cluster_hb_interval = h->interval;
}
if (h->timeout != config->cluster_hb_timeout)
{
LOG(2, 0, 0, "Master set heartbeat timeout to %u (was %u)\n",
h->timeout, config->cluster_hb_timeout);
config->cluster_hb_timeout = h->timeout;
}
// Ok. process the packet...
while ( s > 0) {
type = *((uint32_t *) p);
p += sizeof(uint32_t);
s -= sizeof(uint32_t);
more = *((uint32_t *) p);
p += sizeof(uint32_t);
s -= sizeof(uint32_t);
switch (type) {
case C_CSESSION: { // Compressed session structure.
uint8_t c[ sizeof(sessiont) + 2];
int size;
uint8_t *orig_p = p;
size = rle_decompress((uint8_t **) &p, s, c, sizeof(c) );
s -= (p - orig_p);
// session struct changed with v5
if (hb_ver < 5)
{
if (size != sizeof(struct oldsession)) {
LOG(0, 0, 0, "DANGER: Received a v%d CSESSION that didn't decompress correctly!\n", hb_ver);
// Now what? Should exit! No-longer up to date!
break;
}
cluster_recv_session(more, convert_session((struct oldsession *) c));
break;
}
if (size != sizeof(sessiont) ) { // Ouch! Very very bad!
LOG(0, 0, 0, "DANGER: Received a CSESSION that didn't decompress correctly!\n");
// Now what? Should exit! No-longer up to date!
break;
}
cluster_recv_session(more, c);
break;
}
case C_SESSION:
if (hb_ver < 5)
{
if (s < sizeof(struct oldsession))
goto shortpacket;
cluster_recv_session(more, convert_session((struct oldsession *) p));
p += sizeof(struct oldsession);
s -= sizeof(struct oldsession);
break;
}
if ( s < sizeof(session[more]))
goto shortpacket;
cluster_recv_session(more, p);
p += sizeof(session[more]);
s -= sizeof(session[more]);
break;
case C_CTUNNEL: { // Compressed tunnel structure.
uint8_t c[ sizeof(tunnelt) + 2];
int size;
uint8_t *orig_p = p;
size = rle_decompress((uint8_t **) &p, s, c, sizeof(c));
s -= (p - orig_p);
if (size != sizeof(tunnelt) ) { // Ouch! Very very bad!
LOG(0, 0, 0, "DANGER: Received a CSESSION that didn't decompress correctly!\n");
// Now what? Should exit! No-longer up to date!
break;
}
cluster_recv_tunnel(more, c);
break;
}
case C_TUNNEL:
if ( s < sizeof(tunnel[more]))
goto shortpacket;
cluster_recv_tunnel(more, p);
p += sizeof(tunnel[more]);
s -= sizeof(tunnel[more]);
break;
default:
LOG(0, 0, 0, "DANGER: I received a heartbeat element where I didn't understand the type! (%d)\n", type);
return -1; // can't process any more of the packet!!
}
}
if (config->cluster_master_address != addr)
{
LOG(0, 0, 0, "My master just changed from %s to %s!\n",
fmtaddr(config->cluster_master_address, 0), fmtaddr(addr, 1));
config->cluster_master_address = addr;
}
config->cluster_last_hb = TIME; // Successfully received a heartbeat!
config->cluster_table_version = h->table_version;
return 0;
shortpacket:
LOG(0, 0, 0, "I got an incomplete heartbeat packet! This means I'm probably out of sync!!\n");
return -1;
}
//
// We got a packet on the cluster port!
// Handle pings, lastseens, and heartbeats!
//
int processcluster(char *data, int size, in_addr_t addr)
{
int type, more;
char *p = data;
int s = size;
if (addr == my_address)
return -1; // Ignore it. Something looped back the multicast!
LOG(5, 0, 0, "Process cluster: %d bytes from %s\n", size, fmtaddr(addr, 0));
if (s <= 0) // Any data there??
return -1;
if (s < 8)
goto shortpacket;
type = *((uint32_t *) p);
p += sizeof(uint32_t);
s -= sizeof(uint32_t);
more = *((uint32_t *) p);
p += sizeof(uint32_t);
s -= sizeof(uint32_t);
switch (type) {
case C_PING: // Update the peers table.
return cluster_add_peer(addr, more, (pingt *) p, s);
case C_LASTSEEN: // Catch up a slave (slave missed a packet).
if (!config->cluster_iam_master) { // huh?
LOG(0, 0, 0, "I'm not the master, but I got a C_LASTSEEN from %s?\n", fmtaddr(addr, 0));
return -1;
}
return cluster_catchup_slave(more, addr);
case C_FORWARD: { // Forwarded control packet. pass off to processudp.
struct sockaddr_in a;
a.sin_addr.s_addr = more;
a.sin_port = *(int *) p;
s -= sizeof(int);
p += sizeof(int);
if (!config->cluster_iam_master) { // huh?
LOG(0, 0, 0, "I'm not the master, but I got a C_FORWARD from %s?\n", fmtaddr(addr, 0));
return -1;
}
LOG(4, 0, 0, "Got a forwarded packet... (%s:%d)\n", fmtaddr(more, 0), a.sin_port);
STAT(recv_forward);
processudp(p, s, &a);
return 0;
}
case C_THROTTLE: { // Receive a forwarded packet from a slave.
if (!config->cluster_iam_master) {
LOG(0, 0, 0, "I'm not the master, but I got a C_THROTTLE from %s?\n", fmtaddr(addr, 0));
return -1;
}
tbf_queue_packet(more, p, s); // The TBF id tells wether it goes in or out.
return 0;
}
case C_GARDEN:
// Receive a walled garden packet from a slave.
if (!config->cluster_iam_master) {
LOG(0, 0, 0, "I'm not the master, but I got a C_GARDEN from %s?\n", fmtaddr(addr, 0));
return -1;
}
tun_write(p, s);
return 0;
case C_BYTES:
return cluster_handle_bytes(p, s);
case C_KILL: // The master asked us to die!? (usually because we're too out of date).
if (config->cluster_iam_master) {
LOG(0, 0, 0, "_I_ am master, but I received a C_KILL from %s! (Seq# %d)\n", fmtaddr(addr, 0), more);
return -1;
}
if (more != config->cluster_seq_number) {
LOG(0, 0, 0, "The master asked us to die but the seq number didn't match!?\n");
return -1;
}
if (addr != config->cluster_master_address) {
LOG(0, 0, 0, "Received a C_KILL from %s which doesn't match config->cluster_master_address (%s)\n",
fmtaddr(addr, 0), fmtaddr(config->cluster_master_address, 1));
// We can only warn about it. The master might really have switched!
}
LOG(0, 0, 0, "Received a valid C_KILL: I'm going to die now.\n");
kill(0, SIGTERM);
exit(0); // Lets be paranoid;
return -1; // Just signalling the compiler.
case C_HEARTBEAT:
LOG(4, 0, 0, "Got a heartbeat from %s\n", fmtaddr(addr, 0));
return cluster_process_heartbeat(data, size, more, p, addr);
default:
LOG(0, 0, 0, "Strange type packet received on cluster socket (%d)\n", type);
return -1;
}
return 0;
shortpacket:
LOG(0, 0, 0, "I got a _short_ cluster heartbeat packet! This means I'm probably out of sync!!\n");
return -1;
}
//====================================================================================================
int cmd_show_cluster(struct cli_def *cli, char *command, char **argv, int argc)
{
int i;
if (CLI_HELP_REQUESTED)
return CLI_HELP_NO_ARGS;
cli_print(cli, "Cluster status : %s", config->cluster_iam_master ? "Master" : "Slave" );
cli_print(cli, "My address : %s", fmtaddr(my_address, 0));
cli_print(cli, "VIP address : %s", fmtaddr(config->bind_address, 0));
cli_print(cli, "Multicast address: %s", fmtaddr(config->cluster_address, 0));
cli_print(cli, "Multicast i'face : %s", config->cluster_interface);
if (!config->cluster_iam_master) {
cli_print(cli, "My master : %s (last heartbeat %.1f seconds old)",
config->cluster_master_address
? fmtaddr(config->cluster_master_address, 0)
: "Not defined",
0.1 * (TIME - config->cluster_last_hb));
cli_print(cli, "Uptodate : %s", config->cluster_iam_uptodate ? "Yes" : "No");
cli_print(cli, "Table version # : %" PRIu64, config->cluster_table_version);
cli_print(cli, "Next sequence number expected: %d", config->cluster_seq_number);
cli_print(cli, "%d sessions undefined of %d", config->cluster_undefined_sessions, config->cluster_highest_sessionid);
cli_print(cli, "%d tunnels undefined of %d", config->cluster_undefined_tunnels, config->cluster_highest_tunnelid);
} else {
cli_print(cli, "Table version # : %" PRIu64, config->cluster_table_version);
cli_print(cli, "Next heartbeat # : %d", config->cluster_seq_number);
cli_print(cli, "Highest session : %d", config->cluster_highest_sessionid);
cli_print(cli, "Highest tunnel : %d", config->cluster_highest_tunnelid);
cli_print(cli, "%d changes queued for sending", config->cluster_num_changes);
}
cli_print(cli, "%d peers.", num_peers);
if (num_peers)
cli_print(cli, "%20s %10s %8s", "Address", "Basetime", "Age");
for (i = 0; i < num_peers; ++i) {
cli_print(cli, "%20s %10u %8d", fmtaddr(peers[i].peer, 0),
peers[i].basetime, TIME - peers[i].timestamp);
}
return CLI_OK;
}
//
// Simple run-length-encoding compression.
// Format is
// 1 byte < 128 = count of non-zero bytes following. // Not legal to be zero.
// n non-zero bytes;
// or
// 1 byte > 128 = (count - 128) run of zero bytes. //
// repeat.
// count == 0 indicates end of compressed stream.
//
// Compress from 'src' into 'dst'. return number of bytes
// used from 'dst'.
// Updates *src_p to indicate 1 past last bytes used.
//
// We could get an extra byte in the zero runs by storing (count-1)
// but I'm playing it safe.
//
// Worst case is a 50% expansion in space required (trying to
// compress { 0x00, 0x01 } * N )
static int rle_compress(uint8_t **src_p, int ssize, uint8_t *dst, int dsize)
{
int count;
int orig_dsize = dsize;
uint8_t *x, *src;
src = *src_p;
while (ssize > 0 && dsize > 2) {
count = 0;
x = dst++; --dsize; // Reserve space for count byte..
if (*src) { // Copy a run of non-zero bytes.
while (*src && count < 127 && ssize > 0 && dsize > 1) { // Count number of non-zero bytes.
*dst++ = *src++;
--dsize; --ssize;
++count;
}
*x = count; // Store number of non-zero bytes. Guarenteed to be non-zero!
} else { // Compress a run of zero bytes.
while (*src == 0 && count < 127 && ssize > 0) {
++src;
--ssize;
++count;
}
*x = count | 0x80 ;
}
}
*dst++ = 0x0; // Add Stop byte.
--dsize;
*src_p = src;
return (orig_dsize - dsize);
}
//
// Decompress the buffer into **p.
// 'psize' is the size of the decompression buffer available.
//
// Returns the number of bytes decompressed.
//
// Decompresses from '*src_p' into 'dst'.
// Return the number of dst bytes used.
// Updates the 'src_p' pointer to point to the
// first un-used byte.
static int rle_decompress(uint8_t **src_p, int ssize, uint8_t *dst, int dsize)
{
int count;
int orig_dsize = dsize;
char *src = *src_p;
while (ssize >0 && dsize > 0) { // While there's more to decompress, and there's room in the decompress buffer...
count = *src++; --ssize; // get the count byte from the source.
if (count == 0x0) // End marker reached? If so, finish.
break;
if (count & 0x80) { // Decompress a run of zeros
for (count &= 0x7f ; count > 0 && dsize > 0; --count) {
*dst++ = 0x0;
--dsize;
}
} else { // Copy run of non-zero bytes.
for ( ; count > 0 && ssize && dsize; --count) { // Copy non-zero bytes across.
*dst++ = *src++;
--ssize; --dsize;
}
}
}
*src_p = src;
return (orig_dsize - dsize);
}
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