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restore: snapct handling peer ip:port duplicates #8494

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1add363
restore: snapct handling peer ip:port duplicates
jvarela-jump Feb 26, 2026
6b035f2
restore: snapct gossip peer dup v2
jvarela-jump Feb 27, 2026
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119 changes: 91 additions & 28 deletions src/discof/restore/fd_snapct_tile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,8 +23,6 @@
#define NAME "snapct"

/* FIXME: Do a finishing pass over the default.toml config options / comments */
/* FIXME: Make the code more strict about duplicate IP:port's */

#define GOSSIP_PEERS_MAX (FD_CONTACT_INFO_TABLE_SIZE)
#define SERVER_PEERS_MAX (FD_TOPO_SNAPSHOTS_SERVERS_MAX_RESOLVED)
#define TOTAL_PEERS_MAX (GOSSIP_PEERS_MAX + SERVER_PEERS_MAX)
Expand Down Expand Up @@ -1046,6 +1044,50 @@ after_credit( fd_snapct_tile_t * ctx,
}
}

/* gossip_addr_is_duplicate returns 1 if addr is already in use by
any other peer or configured server, 0 otherwise. */
static int
gossip_addr_is_duplicate( fd_snapct_tile_t const * ctx,
fd_ip4_port_t addr,
fd_pubkey_t const * exclude_pubkey ) {
/* Check configured servers */
for( ulong i=0UL; i<ctx->config.sources.servers_cnt; i++ ) {
if( addr.l==ctx->config.sources.servers[ i ].addr.l ) return 1;
}
/* Check allowed gossip peers */
for( gossip_ci_map_iter_t iter = gossip_ci_map_iter_init( ctx->gossip.ci_map, ctx->gossip.ci_table );
!gossip_ci_map_iter_done( iter, ctx->gossip.ci_map, ctx->gossip.ci_table );
iter = gossip_ci_map_iter_next( iter, ctx->gossip.ci_map, ctx->gossip.ci_table ) ) {
gossip_ci_entry_t const * other = gossip_ci_map_iter_ele_const( iter, ctx->gossip.ci_map, ctx->gossip.ci_table );
if( other->rpc_addr.l==addr.l && !fd_pubkey_eq( &other->pubkey, exclude_pubkey ) ) {
return 1;
}
}
return 0;
}

static int
remove_gossip_entry( fd_snapct_tile_t * ctx,
ulong idx ) {
FD_TEST( idx<GOSSIP_PEERS_MAX );
gossip_ci_entry_t * entry = ctx->gossip.ci_table + idx;
ulong rem_idx = gossip_ci_map_idx_remove( ctx->gossip.ci_map, &entry->pubkey, ULONG_MAX, ctx->gossip.ci_table );
if( rem_idx==ULONG_MAX ) return -1;
FD_TEST( entry->allowed && rem_idx==idx );
fd_ip4_port_t addr = entry->rpc_addr;
if( FD_LIKELY( !!addr.l ) ) {
int removed = fd_ssping_remove( ctx->ssping, addr );
if( FD_LIKELY( removed ) ) fd_sspeer_selector_remove( ctx->selector, addr );
}
if( !ctx->config.sources.gossip.allow_any ) {
FD_BASE58_ENCODE_32_BYTES( entry->pubkey.uc, pubkey_b58 );
FD_LOG_WARNING(( "allowed gossip peer removed with public key `%s` and RPC address `" FD_IP4_ADDR_FMT ":%hu`",
pubkey_b58, FD_IP4_ADDR_FMT_ARGS( addr.addr ), fd_ushort_bswap( addr.port ) ));
}
fd_memset( entry, 0, sizeof(*entry) );
return 0;
}

static void
gossip_frag( fd_snapct_tile_t * ctx,
ulong sig,
Expand All @@ -1063,8 +1105,10 @@ gossip_frag( fd_snapct_tile_t * ctx,
FD_TEST( msg->contact_info->idx<GOSSIP_PEERS_MAX );
fd_pubkey_t const * pubkey = (fd_pubkey_t const *)msg->origin;
gossip_ci_entry_t * entry = ctx->gossip.ci_table + msg->contact_info->idx;
if( FD_UNLIKELY( !fd_pubkey_eq( &entry->pubkey, pubkey ) ) ) {
/* Initialize the new gossip entry, which may or may not be allowed */

/* Initialize the new gossip entry, which may or may not be allowed */
int pubkey_eq = fd_pubkey_eq( &entry->pubkey, pubkey );
if( FD_UNLIKELY( !pubkey_eq ) ) {
FD_TEST( fd_pubkey_check_zero( &entry->pubkey ) );
entry->pubkey = *pubkey;
entry->rpc_addr.l = 0UL;
Expand All @@ -1086,23 +1130,52 @@ gossip_frag( fd_snapct_tile_t * ctx,
}
}
}
FD_TEST( ULONG_MAX==gossip_ci_map_idx_query_const( ctx->gossip.ci_map, pubkey, ULONG_MAX, ctx->gossip.ci_table ) );
if( entry->allowed ) gossip_ci_map_idx_insert( ctx->gossip.ci_map, msg->contact_info->idx, ctx->gossip.ci_table );
FD_TEST( ULONG_MAX==gossip_ci_map_idx_query_const( ctx->gossip.ci_map, pubkey, ULONG_MAX, ctx->gossip.ci_table ) );
/* If the entry is not allowed, clean the entry entirely, since
it will not be added to the map. */
if( !entry->allowed ) fd_memset( entry, 0, sizeof(gossip_ci_entry_t) );
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@cali-jumptrading cali-jumptrading Feb 27, 2026

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hmm... thinking about this, this means every time a gossip peer that is not allowed is received, then we would have to do the pubkey compare and memset every time?

}
if( !entry->allowed ) break;
/* Maybe update the RPC address of a new or existing allowed gossip peer */

/* Update RPC address of a new or existing allowed gossip peer. */
fd_ip4_port_t cur_addr = entry->rpc_addr;
fd_ip4_port_t new_addr;
new_addr.addr = msg->contact_info->value->sockets[ FD_GOSSIP_CONTACT_INFO_SOCKET_RPC ].is_ipv6 ? 0 : msg->contact_info->value->sockets[ FD_GOSSIP_CONTACT_INFO_SOCKET_RPC ].ip4;
new_addr.port = msg->contact_info->value->sockets[ FD_GOSSIP_CONTACT_INFO_SOCKET_RPC ].port;
fd_ip4_port_t new_addr = { .l= 0UL };
if( !msg->contact_info->value->sockets[ FD_GOSSIP_CONTACT_INFO_SOCKET_RPC ].is_ipv6 ) {
new_addr.addr = msg->contact_info->value->sockets[ FD_GOSSIP_CONTACT_INFO_SOCKET_RPC ].ip4;
new_addr.port = msg->contact_info->value->sockets[ FD_GOSSIP_CONTACT_INFO_SOCKET_RPC ].port;
}
int addr_is_new = new_addr.l!=cur_addr.l;

if( FD_UNLIKELY( new_addr.l!=cur_addr.l ) ) {
/* If no change needed, break. */
if( pubkey_eq && !addr_is_new ) break;

/* Process address */
int addr_is_dup = !!new_addr.l && gossip_addr_is_duplicate( ctx, new_addr, pubkey );

if( FD_UNLIKELY( addr_is_dup ) ) {
/* Duplicate case. */
FD_BASE58_ENCODE_32_BYTES( pubkey->uc, dup_b58 );
FD_LOG_WARNING(( "gossip peer `%s` advertises duplicate RPC address " FD_IP4_ADDR_FMT ":%hu, skipping",
dup_b58, FD_IP4_ADDR_FMT_ARGS( new_addr.addr ), fd_ushort_bswap( new_addr.port ) ));
if( pubkey_eq ) {
FD_TEST( !remove_gossip_entry( ctx, msg->contact_info->idx ) );
} else {
/* Clear the entry when the address is a duplicate. This
will allow us to process the same peer next time it is
received, potentially with a different address. */
fd_memset( entry, 0, sizeof(gossip_ci_entry_t) );
}
} else {
/* New address case. */
entry->rpc_addr = new_addr;
if( FD_LIKELY( !!cur_addr.l ) ) {
int removed = fd_ssping_remove( ctx->ssping, cur_addr );
if( FD_LIKELY( removed ) ) fd_sspeer_selector_remove( ctx->selector, cur_addr );
}
if( FD_LIKELY( !!new_addr.l ) ) fd_ssping_add( ctx->ssping, new_addr );
if( FD_LIKELY( !!new_addr.l ) ) {
fd_ssping_add( ctx->ssping, new_addr );
}
/* Log */
if( !ctx->config.sources.gossip.allow_any ) {
FD_BASE58_ENCODE_32_BYTES( pubkey->uc, pubkey_b58 );
if( FD_LIKELY( !!new_addr.l ) ) {
Expand All @@ -1113,25 +1186,15 @@ gossip_frag( fd_snapct_tile_t * ctx,
}
}
}

/* Insert in map. */
if( FD_UNLIKELY( !pubkey_eq && entry->allowed && !addr_is_dup ) ) {
gossip_ci_map_idx_insert( ctx->gossip.ci_map, msg->contact_info->idx, ctx->gossip.ci_table );
}
break;
}
case FD_GOSSIP_UPDATE_TAG_CONTACT_INFO_REMOVE: {
FD_TEST( msg->contact_info_remove->idx<GOSSIP_PEERS_MAX );
gossip_ci_entry_t * entry = ctx->gossip.ci_table + msg->contact_info_remove->idx;
ulong rem_idx = gossip_ci_map_idx_remove( ctx->gossip.ci_map, &entry->pubkey, ULONG_MAX, ctx->gossip.ci_table );
if( rem_idx==ULONG_MAX ) break;
FD_TEST( entry->allowed && rem_idx==msg->contact_info_remove->idx );
fd_ip4_port_t addr = entry->rpc_addr;
if( FD_LIKELY( !!addr.l ) ) {
int removed = fd_ssping_remove( ctx->ssping, addr );
if( FD_LIKELY( removed ) ) fd_sspeer_selector_remove( ctx->selector, addr );
}
if( !ctx->config.sources.gossip.allow_any ) {
FD_BASE58_ENCODE_32_BYTES( entry->pubkey.uc, pubkey_b58 );
FD_LOG_WARNING(( "allowed gossip peer removed with public key `%s` and RPC address `" FD_IP4_ADDR_FMT ":%hu`",
pubkey_b58, FD_IP4_ADDR_FMT_ARGS( addr.addr ), fd_ushort_bswap( addr.port ) ));
}
fd_memset( entry, 0, sizeof(*entry) );
FD_TEST( !remove_gossip_entry( ctx, msg->contact_info_remove->idx ) );
break;
}
case FD_GOSSIP_UPDATE_TAG_SNAPSHOT_HASHES: {
Expand Down
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