package/network/services/dnsmasq/patches/0003-Add-logging-for-DNS-error-returns-from-upstream-and-.patch

   1 From 07ed585c38d8f7c0a18470d2e79cf46ea92ea96a Mon Sep 17 00:00:00 2001
   2 From: Simon Kelley <simon@thekelleys.org.uk>
   3 Date: Fri, 4 May 2018 21:52:22 +0100
   4 Subject: [PATCH 03/10] Add logging for DNS error returns from upstream and
   5  local configuration.
   6
   7 Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
   8 ---
   9  src/cache.c   | 13 +++++++++++++
  10  src/dnsmasq.h |  7 ++++++-
  11  src/forward.c | 25 +++++++++++++++++++------
  12  src/rfc1035.c | 19 ++++++++++++++-----
  13  4 files changed, 52 insertions(+), 12 deletions(-)
  14
  15 --- a/src/cache.c
  16 +++ b/src/cache.c
  17 @@ -1598,6 +1598,19 @@ void log_query(unsigned int flags, char
  18      {
  19        if (flags & F_KEYTAG)
  20         sprintf(daemon->addrbuff, arg, addr->addr.log.keytag, addr->addr.log.algo, addr->addr.log.digest);
  21 +      else if (flags & F_RCODE)
  22 +       {
  23 +         unsigned int rcode = addr->addr.rcode.rcode;
  24 +
  25 +          if (rcode == SERVFAIL)
  26 +            dest = "SERVFAIL";
  27 +          else if (rcode == REFUSED)
  28 +            dest = "REFUSED";
  29 +          else if (rcode == NOTIMP)
  30 +            dest = "not implemented";
  31 +          else
  32 +            sprintf(daemon->addrbuff, "%u", rcode);
  33 +       }
  34        else
  35         {
  36  #ifdef HAVE_IPV6
  37 --- a/src/dnsmasq.h
  38 +++ b/src/dnsmasq.h
  39 @@ -268,7 +268,11 @@ struct all_addr {
  40      /* for log_query */
  41      struct {
  42        unsigned short keytag, algo, digest;
  43 -    } log;
  44 +    } log;
  45 +    /* for log_query */
  46 +    struct {
  47 +      unsigned int rcode;
  48 +    } rcode;
  49      /* for cache_insert of DNSKEY, DS */
  50      struct {
  51        unsigned short class, type;
  52 @@ -459,6 +463,7 @@ struct crec {
  53  #define F_IPSET     (1u<<26)
  54  #define F_NOEXTRA   (1u<<27)
  55  #define F_SERVFAIL  (1u<<28)
  56 +#define F_RCODE     (1u<<29)
  57
  58  /* Values of uid in crecs with F_CONFIG bit set. */
  59  #define SRC_INTERFACE 0
  60 --- a/src/forward.c
  61 +++ b/src/forward.c
  62 @@ -563,6 +563,7 @@ static size_t process_reply(struct dns_h
  63    unsigned char *pheader, *sizep;
  64    char **sets = 0;
  65    int munged = 0, is_sign;
  66 +  unsigned int rcode = RCODE(header);
  67    size_t plen;
  68
  69    (void)ad_reqd;
  70 @@ -593,6 +594,9 @@ static size_t process_reply(struct dns_h
  71
  72    if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign, NULL)))
  73      {
  74 +      /* Get extended RCODE. */
  75 +      rcode |= sizep[2] << 4;
  76 +
  77        if (check_subnet && !check_source(header, plen, pheader, query_source))
  78         {
  79           my_syslog(LOG_WARNING, _("discarding DNS reply: subnet option mismatch"));
  80 @@ -641,11 +645,20 @@ static size_t process_reply(struct dns_h
  81    if (!is_sign && !option_bool(OPT_DNSSEC_PROXY))
  82       header->hb4 &= ~HB4_AD;
  83
  84 -  if (OPCODE(header) != QUERY || (RCODE(header) != NOERROR && RCODE(header) != NXDOMAIN))
  85 +  if (OPCODE(header) != QUERY)
  86      return resize_packet(header, n, pheader, plen);
  87 +
  88 +  if (rcode != NOERROR && rcode != NXDOMAIN)
  89 +    {
  90 +      struct all_addr a;
  91 +      a.addr.rcode.rcode = rcode;
  92 +      log_query(F_UPSTREAM | F_RCODE, "error", &a, NULL);
  93 +
  94 +      return resize_packet(header, n, pheader, plen);
  95 +    }
  96
  97    /* Complain loudly if the upstream server is non-recursive. */
  98 -  if (!(header->hb4 & HB4_RA) && RCODE(header) == NOERROR &&
  99 +  if (!(header->hb4 & HB4_RA) && rcode == NOERROR &&
 100        server && !(server->flags & SERV_WARNED_RECURSIVE))
 101      {
 102        prettyprint_addr(&server->addr, daemon->namebuff);
 103 @@ -654,7 +667,7 @@ static size_t process_reply(struct dns_h
 104         server->flags |= SERV_WARNED_RECURSIVE;
 105      }
 106
 107 -  if (daemon->bogus_addr && RCODE(header) != NXDOMAIN &&
 108 +  if (daemon->bogus_addr && rcode != NXDOMAIN &&
 109        check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now))
 110      {
 111        munged = 1;
 112 @@ -666,7 +679,7 @@ static size_t process_reply(struct dns_h
 113      {
 114        int doctored = 0;
 115
 116 -      if (RCODE(header) == NXDOMAIN &&
 117 +      if (rcode == NXDOMAIN &&
 118           extract_request(header, n, daemon->namebuff, NULL) &&
 119           check_for_local_domain(daemon->namebuff, now))
 120         {
 121 @@ -1090,7 +1103,7 @@ void reply_query(int fd, int family, tim
 122               if (status == STAT_BOGUS && extract_request(header, n, daemon->namebuff, NULL))
 123                 domain = daemon->namebuff;
 124
 125 -             log_query(F_KEYTAG | F_SECSTAT, domain, NULL, result);
 126 +             log_query(F_SECSTAT, domain, NULL, result);
 127             }
 128
 129           if (status == STAT_SECURE)
 130 @@ -1948,7 +1961,7 @@ unsigned char *tcp_request(int confd, ti
 131                           if (status == STAT_BOGUS && extract_request(header, m, daemon->namebuff, NULL))
 132                             domain = daemon->namebuff;
 133
 134 -                         log_query(F_KEYTAG | F_SECSTAT, domain, NULL, result);
 135 +                         log_query(F_SECSTAT, domain, NULL, result);
 136
 137                           if (status == STAT_BOGUS)
 138                             {
 139 --- a/src/rfc1035.c
 140 +++ b/src/rfc1035.c
 141 @@ -926,12 +926,11 @@ unsigned int extract_request(struct dns_
 142    return F_QUERY;
 143  }
 144
 145 -
 146  size_t setup_reply(struct dns_header *header, size_t qlen,
 147                 struct all_addr *addrp, unsigned int flags, unsigned long ttl)
 148  {
 149    unsigned char *p;
 150 -
 151 +
 152    if (!(p = skip_questions(header, qlen)))
 153      return 0;
 154
 155 @@ -948,7 +947,12 @@ size_t setup_reply(struct dns_header *he
 156    else if (flags == F_NXDOMAIN)
 157      SET_RCODE(header, NXDOMAIN);
 158    else if (flags == F_SERVFAIL)
 159 -    SET_RCODE(header, SERVFAIL);
 160 +    {
 161 +      struct all_addr a;
 162 +      a.addr.rcode.rcode = SERVFAIL;
 163 +      log_query(F_CONFIG | F_RCODE, "error", &a, NULL);
 164 +      SET_RCODE(header, SERVFAIL);
 165 +    }
 166    else if (flags == F_IPV4)
 167      { /* we know the address */
 168        SET_RCODE(header, NOERROR);
 169 @@ -966,8 +970,13 @@ size_t setup_reply(struct dns_header *he
 170      }
 171  #endif
 172    else /* nowhere to forward to */
 173 -    SET_RCODE(header, REFUSED);
 174 -
 175 +    {
 176 +      struct all_addr a;
 177 +      a.addr.rcode.rcode = REFUSED;
 178 +      log_query(F_CONFIG | F_RCODE, "error", &a, NULL);
 179 +      SET_RCODE(header, REFUSED);
 180 +    }
 181 +
 182    return p - (unsigned char *)header;
 183  }
 184