X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/c5e4c2cfc092317c1e3ceb0f654f880f6a8573f4..15e84554e1274f1f2d8dd7e389b148c8e6309198:/cluster.c?ds=sidebyside diff --git a/cluster.c b/cluster.c index 5ad3ff3..fdfe2dd 100644 --- a/cluster.c +++ b/cluster.c @@ -1,8 +1,10 @@ // L2TPNS Clustering Stuff -// $Id: cluster.c,v 1.1 2003-12-16 07:07:39 fred_nerk Exp $ #include #include +char const *cvs_id_cluster = "$Id: cluster.c,v 1.19 2004-11-29 02:17:17 bodea Exp $"; + +#include +#include #include -#include #include #include #include @@ -15,71 +17,1511 @@ #include #include #include +#include + +#include "l2tpns.h" #include "cluster.h" +#include "util.h" +#include "tbf.h" -int cluster_sockfd = 0; -int cluster_server = 0; -uint32_t vip_address; -extern int debug; -void _log_hex(int level, const char *title, const char *data, int maxsize); -#define log_hex(a,b,c,d) -#ifndef log_hex -#define log_hex(a,b,c,d) do{if (a > debug) _log_hex(a,b,c,d);}while (0) +#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. + +ipt 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. + +#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 { + u32 peer; + time_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(u8 ** src_p, int ssize, u8 *dst, int dsize); +static int rle_compress(u8 ** src_p, int ssize, u8 *dst, int dsize); + +// // Create a listening socket -int cluster_init(uint32_t bind_address, int server) +// +// 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 = 0; + + 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)); + + 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) +{ + * ( (u32*)(*p) ) = type; + *p += sizeof(u32); + + * ( (u32*)(*p) ) = more; + *p += sizeof(u32); + + 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(u32 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(u32 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, u32 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) { - struct sockaddr_in addr; + 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_count[walk_session_number].cin && !sess_count[walk_session_number].cout) + continue; // Unused. Skip it. + + b[c].sid = walk_session_number; + b[c].in = sess_count[walk_session_number].cin; + b[c].out = sess_count[walk_session_number].cout; + + if (++c > MAX_B_RECS) // Send a max of 400 elements in a packet. + break; + + // Reset counters. + sess_count[walk_session_number].cin = sess_count[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].tunnel == T_FREE) { // Unused session. Add to free list. + session[last_free].next = i; + session[i].next = 0; + last_free = i; + } + + // Reset all the idle timeouts.. + session[i].last_packet = time_now; + + // Accumulate un-sent byte counters. + session[i].cin += sess_count[i].cin; + session[i].cout += sess_count[i].cout; + session[i].total_cin += sess_count[i].cin; + session[i].total_cout += sess_count[i].cout; + + sess_count[i].cin = sess_count[i].cout = 0; + + session[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); + + if (session[i].tunnel != T_FREE && i > config->cluster_highest_sessionid) + 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) { + session[i].tunnel = 0; // Defined. + continue; + } + if (session[i].tunnel != T_UNDEF) + continue; + ++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) { + tunnel[i].state = TUNNELFREE; // Defined. + continue; + } + if (tunnel[i].state != TUNNELUNDEF) + continue; + ++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. + u8 c[sizeof(sessiont) * 2]; // Bigger than worst case. + u8 *d = (u8 *) &session[id]; + u8 *orig = d; + int size; + + size = rle_compress( &d, sizeof(sessiont), c, sizeof(c) ); - vip_address = bind_address; - cluster_server = !!server; + // 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; - cluster_sockfd = socket(AF_INET, SOCK_DGRAM, UDP); + case C_CTUNNEL: { // Compressed C_TUNNEL + u8 c[sizeof(tunnelt) * 2]; // Bigger than worst case. + u8 *d = (u8 *) &tunnel[id]; + u8 *orig = d; + int size; - memset(&addr, 0, sizeof(addr)); - addr.sin_family = AF_INET; - addr.sin_port = htons(cluster_server ? CLUSTERPORT : CLUSTERCLIENTPORT); - addr.sin_addr.s_addr = INADDR_ANY; - setsockopt(cluster_sockfd, SOL_SOCKET, SO_REUSEADDR, &addr, sizeof(addr)); - if (bind(cluster_sockfd, (void *) &addr, sizeof(addr)) < 0) - { - perror("bind"); - exit(-1); - } + size = rle_compress( &d, sizeof(tunnelt), c, sizeof(c) ); - return cluster_sockfd; + // 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; } -int cluster_send_message(unsigned long ip_address, uint32_t vip, char type, void *data, int datalen) +// +// Send a heartbeat, incidently sending out any queued changes.. +// +void cluster_heartbeat() { - size_t l = 1 + sizeof(uint32_t) + datalen; - char *buf = NULL; - struct sockaddr_in addr = {0}; + int i, count = 0, tcount = 0; + char buff[MAX_HEART_SIZE + sizeof(heartt) + sizeof(int) ]; + heartt h; + char *p = buff; - if (!cluster_sockfd) return -1; - if (!ip_address) return 0; + if (!config->cluster_iam_master) // Only the master does this. + return; - buf = calloc(l, 1); - *(uint32_t *)(buf) = htonl(vip); - *(char *)(buf+sizeof(uint32_t)) = type; + // Fill out the heartbeat header. + memset(&h, 0, sizeof(h)); - if (data && datalen > 0) - memcpy((char *)(buf + sizeof(uint32_t) + 1), data, datalen); + 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; - addr.sin_addr.s_addr = ip_address; - addr.sin_port = htons(cluster_server ? CLUSTERCLIENTPORT : CLUSTERPORT); - addr.sin_family = AF_INET; + add_type(&p, C_HEARTBEAT, HB_VERSION, (char*) &h, sizeof(h)); - log_hex(4, "Cluster send", buf, l); + for (i = 0; i < config->cluster_num_changes; ++i) { + hb_add_type(&p, cluster_changes[i].type, cluster_changes[i].id); + } - if (sendto(cluster_sockfd, buf, l, MSG_NOSIGNAL, (void *) &addr, sizeof(addr)) < 0) - { - perror("sendto"); - free(buf); + 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", 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(u32) * 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(u32) * 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", p - buff); + kill(0, SIGTERM); + exit(1); + } + + LOG(3, 0, 0, "Sending heartbeat #%d with %d changes (%d x-sess, %d x-tunnels, %d highsess, %d hightun, size %d)\n", + h.seq, config->cluster_num_changes, count, tcount, config->cluster_highest_sessionid, + config->cluster_highest_tunnelid, (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; + } + + 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, u32 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 slaved 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(u32 peer, time_t basetime, pingt *pp, int size) +{ + int i; + u32 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; + 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 , u8 * 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, u8 *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; +} + + +// +// Process a heartbeat.. +// +static int cluster_process_heartbeat(u8 * data, int size, int more, u8 * p, u32 addr) +{ + heartt * h; + int s = size - (p-data); + int i, type; + +#if HB_VERSION != 3 +# error "need to update cluster_process_heartbeat()" +#endif + + // we handle version 2+ + if (more < 2 || more > HB_VERSION) { + LOG(0, 0, 0, "Received a heartbeat version that I don't support (%d)!\n", more); + 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 packet claiming to be from a master but _I_ am the master!\n"); + if (!h->basetime) { + LOG(0, 0, 0, "Heartbeat from addr %s with zero basetime!\n", fmtaddr(addr, 0)); + return -1; // Skip it. + } + if (basetime > h->basetime) { + LOG(0, 0, 0, "They're (%s) an older master than me so I'm gone!\n", fmtaddr(addr, 0)); + kill(0, SIGTERM); + exit(1); + } + if (basetime == h->basetime && 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! + LOG(1, 0, 0, "HB: Got seq# %d but was expecting %d. asking for resend.\n", h->seq, config->cluster_seq_number); + + 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 (more > 2) // reserved section of heartt was not initialized prior to v3 + { + 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 = * ((u32*) p); + p += sizeof(u32); + s -= sizeof(u32); + + more = * ((u32*) p); + p += sizeof(u32); + s -= sizeof(u32); + + switch (type) { + case C_CSESSION: { // Compressed session structure. + u8 c [ sizeof(sessiont) + 2]; + int size; + u8 * orig_p = p; + + size = rle_decompress((u8 **) &p, s, c, sizeof(c) ); + s -= (p - orig_p); + + 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 ( 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. + u8 c [ sizeof(tunnelt) + 2]; + int size; + u8 * orig_p = p; + + size = rle_decompress( (u8 **) &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! + return 0; + +shortpacket: + LOG(0, 0, 0, "I got an incomplete heartbeat packet! This means I'm probably out of sync!!\n"); return -1; - } - free(buf); +} + +// +// We got a packet on the cluster port! +// Handle pings, lastseens, and heartbeats! +// +int processcluster(char * data, int size, u32 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 = * ((u32*) p); + p += sizeof(u32); + s -= sizeof(u32); + + more = * ((u32*) p); + p += sizeof(u32); + s -= sizeof(u32); + + 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). + 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, "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, "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 %10d %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(u8 ** src_p, int ssize, u8 *dst, int dsize) +{ + int count; + int orig_dsize = dsize; + u8 * 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(u8 ** src_p, int ssize, u8 *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; - return 0; + 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); }