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networktable.c
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networktable.c
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/* Pi-hole: A black hole for Internet advertisements
* (c) 2017 Pi-hole, LLC (https://pi-hole.net)
* Network-wide ad blocking via your own hardware.
*
* FTL Engine
* Network table routines
*
* This file is copyright under the latest version of the EUPL.
* Please see LICENSE file for your rights under this license. */
#include "FTL.h"
#include "shmem.h"
#include "sqlite3.h"
#define ARPCACHE "/proc/net/arp"
// Private prototypes
static char* getMACVendor(const char* hwaddr);
bool create_network_table(void)
{
bool ret;
// Create network table in the database
ret = dbquery("CREATE TABLE network ( id INTEGER PRIMARY KEY NOT NULL, " \
"ip TEXT NOT NULL, " \
"hwaddr TEXT NOT NULL, " \
"interface TEXT NOT NULL, " \
"name TEXT, " \
"firstSeen INTEGER NOT NULL, " \
"lastQuery INTEGER NOT NULL, " \
"numQueries INTEGER NOT NULL," \
"macVendor TEXT);");
if(!ret){ dbclose(); return false; }
// Update database version to 3
ret = db_set_FTL_property(DB_VERSION, 3);
if(!ret){ dbclose(); return false; }
return true;
}
// Read kernel's ARP cache using procfs
void parse_arp_cache(void)
{
FILE* arpfp = NULL;
// Try to access the kernel's ARP cache
if((arpfp = fopen(ARPCACHE, "r")) == NULL)
{
logg("WARN: Opening of %s failed!", ARPCACHE);
logg(" Message: %s", strerror(errno));
return;
}
// Open database file
if(!dbopen())
{
logg("read_arp_cache() - Failed to open DB");
fclose(arpfp);
return;
}
// Start ARP timer
if(config.debug & DEBUG_ARP) timer_start(ARP_TIMER);
// Prepare buffers
char * linebuffer = NULL;
size_t linebuffersize = 0;
char ip[100], mask[100], hwaddr[100], iface[100];
int type, flags, entries = 0;
time_t now = time(NULL);
// Start collecting database commands
dbquery("BEGIN TRANSACTION");
// Read ARP cache line by line
while(getline(&linebuffer, &linebuffersize, arpfp) != -1)
{
int num = sscanf(linebuffer, "%99s 0x%x 0x%x %99s %99s %99s\n",
ip, &type, &flags, hwaddr, mask, iface);
// Skip header and empty lines
if (num < 4)
continue;
// Skip incomplete entires, i.e., entries without C (complete) flag
if(!(flags & 0x02))
continue;
// Get ID of this device in our network database. If it cannot be found, then this is a new device
// We match both IP *and* MAC address
// Same MAC, two IPs: Non-deterministic DHCP server, treat as two entries
// Same IP, two MACs: Either non-deterministic DHCP server or (almost) full DHCP address pool
// We can run this SELECT inside the currently active transaction as only the
// changed to the database are collected for latter commitment. Read-only access
// such as this SELECT command will be executed immediately on the database.
char* querystr = NULL;
int ret = asprintf(&querystr, "SELECT id FROM network WHERE ip = \'%s\' AND hwaddr = \'%s\';", ip, hwaddr);
if(querystr == NULL || ret < 0)
{
logg("Memory allocation failed in parse_arp_cache (%i)", ret);
break;
}
// Perform SQL query
int dbID = db_query_int(querystr);
free(querystr);
if(dbID == DB_FAILED)
{
// SQLite error
break;
}
// If we reach this point, we can check if this client
// is known to pihole-FTL
// false = do not create a new record if the client is
// unknown (only DNS requesting clients do this)
lock_shm();
int clientID = findClientID(ip, false);
// This client is known (by its IP address) to pihole-FTL if
// findClientID() returned a non-negative index
bool clientKnown = clientID >= 0;
// Get hostname of this client if the client is known
const char *hostname = "";
if(clientKnown)
{
validate_access("clients", clientID, true, __LINE__, __FUNCTION__, __FILE__);
hostname = getstr(clients[clientID].namepos);
}
// Device not in database, add new entry
if(dbID == DB_NODATA)
{
char* macVendor = getMACVendor(hwaddr);
dbquery("INSERT INTO network "\
"(ip,hwaddr,interface,firstSeen,lastQuery,numQueries,name,macVendor) "\
"VALUES (\'%s\',\'%s\',\'%s\',%lu, %ld, %u, \'%s\', \'%s\');",\
ip, hwaddr, iface, now,
clientKnown ? clients[clientID].lastQuery : 0L,
clientKnown ? clients[clientID].numQueriesARP : 0u,
hostname,
macVendor);
free(macVendor);
}
// Device in database AND client known to Pi-hole
else if(clientKnown)
{
// Update lastQuery. Only use new value if larger
// clients[clientID].lastQuery may be zero if this
// client is only known from a database entry but has
// not been seen since then
dbquery("UPDATE network "\
"SET lastQuery = MAX(lastQuery, %ld) "\
"WHERE id = %i;",\
clients[clientID].lastQuery, dbID);
// Update numQueries. Add queries seen since last update
// and reset counter afterwards
dbquery("UPDATE network "\
"SET numQueries = numQueries + %u "\
"WHERE id = %i;",\
clients[clientID].numQueriesARP, dbID);
clients[clientID].numQueriesARP = 0;
// Store hostname if available
if(strlen(hostname) > 0)
{
// Store host name
dbquery("UPDATE network "\
"SET name = \'%s\' "\
"WHERE id = %i;",\
hostname, dbID);
}
}
// else:
// Device in database but not known to Pi-hole: No action required
unlock_shm();
// Count number of processed ARP cache entries
entries++;
}
// Actually update the database
dbquery("COMMIT");
// Debug logging
if(config.debug & DEBUG_ARP) logg("ARP table processing (%i entries) took %.1f ms", entries, timer_elapsed_msec(ARP_TIMER));
// Close file handle
fclose(arpfp);
// Close database connection
dbclose();
}
static char* getMACVendor(const char* hwaddr)
{
struct stat st;
if(stat(FTLfiles.macvendordb, &st) != 0)
{
// File does not exist
if(config.debug & DEBUG_ARP) logg("getMACVenor(%s): %s does not exist", hwaddr, FTLfiles.macvendordb);
return strdup("");
}
else if(strlen(hwaddr) != 17)
{
// MAC address is incomplete
if(config.debug & DEBUG_ARP) logg("getMACVenor(%s): MAC invalid (length %zu)", hwaddr, strlen(hwaddr));
return strdup("");
}
sqlite3 *macdb;
int rc = sqlite3_open_v2(FTLfiles.macvendordb, &macdb, SQLITE_OPEN_READONLY, NULL);
if( rc ){
logg("getMACVendor(%s) - SQL error (%i): %s", hwaddr, rc, sqlite3_errmsg(macdb));
sqlite3_close(macdb);
return strdup("");
}
char *querystr = NULL;
// Only keep "XX:YY:ZZ" (8 characters)
char * hwaddrshort = strdup(hwaddr);
hwaddrshort[8] = '\0';
rc = asprintf(&querystr, "SELECT vendor FROM macvendor WHERE mac LIKE \'%s\';", hwaddrshort);
if(rc < 1)
{
logg("getMACVendor(%s) - Allocation error (%i)", hwaddr, rc);
sqlite3_close(macdb);
return strdup("");
}
free(hwaddrshort);
sqlite3_stmt* stmt;
rc = sqlite3_prepare_v2(macdb, querystr, -1, &stmt, NULL);
if( rc ){
logg("getMACVendor(%s) - SQL error prepare (%s, %i): %s", hwaddr, querystr, rc, sqlite3_errmsg(macdb));
sqlite3_close(macdb);
return strdup("");
}
free(querystr);
char *vendor = NULL;
rc = sqlite3_step(stmt);
if(rc == SQLITE_ROW)
{
vendor = strdup((char*)sqlite3_column_text(stmt, 0));
}
else
{
// Not found
vendor = strdup("");
}
if(rc != SQLITE_DONE && rc != SQLITE_ROW)
{
// Error
logg("getMACVendor(%s) - SQL error step (%i): %s", hwaddr, rc, sqlite3_errmsg(macdb));
}
sqlite3_finalize(stmt);
sqlite3_close(macdb);
return vendor;
}
void updateMACVendorRecords()
{
struct stat st;
if(stat(FTLfiles.macvendordb, &st) != 0)
{
// File does not exist
if(config.debug & DEBUG_ARP) logg("updateMACVendorRecords(): %s does not exist", FTLfiles.macvendordb);
return;
}
sqlite3 *db;
int rc = sqlite3_open_v2(FTLfiles.db, &db, SQLITE_OPEN_READWRITE, NULL);
if( rc ){
logg("updateMACVendorRecords() - SQL error (%i): %s", rc, sqlite3_errmsg(db));
sqlite3_close(db);
return;
}
sqlite3_stmt* stmt;
const char* selectstr = "SELECT id,hwaddr FROM network;";
rc = sqlite3_prepare_v2(db, selectstr, -1, &stmt, NULL);
if( rc ){
logg("updateMACVendorRecords() - SQL error prepare (%s, %i): %s", selectstr, rc, sqlite3_errmsg(db));
sqlite3_close(db);
return;
}
while((rc = sqlite3_step(stmt)) == SQLITE_ROW)
{
const int id = sqlite3_column_int(stmt, 0);
char* hwaddr = strdup((char*)sqlite3_column_text(stmt, 1));
// Get vendor for MAC
char* vendor = getMACVendor(hwaddr);
free(hwaddr);
hwaddr = NULL;
// Prepare UPDATE statement
char *updatestr = NULL;
if(asprintf(&updatestr, "UPDATE network SET macVendor = \'%s\' WHERE id = %i", vendor, id) < 1)
{
logg("updateMACVendorRecords() - Allocation error 2");
free(vendor);
break;
}
// Execute prepared statement
char *zErrMsg = NULL;
rc = sqlite3_exec(db, updatestr, NULL, NULL, &zErrMsg);
if( rc != SQLITE_OK ){
logg("updateMACVendorRecords() - SQL exec error: %s (%i): %s", updatestr, rc, zErrMsg);
sqlite3_free(zErrMsg);
free(updatestr);
free(vendor);
break;
}
// Free allocated memory
free(updatestr);
free(vendor);
}
if(rc != SQLITE_DONE)
{
// Error
logg("updateMACVendorRecords() - SQL error step (%i): %s", rc, sqlite3_errmsg(db));
}
sqlite3_finalize(stmt);
sqlite3_close(db);
}