summaryrefslogtreecommitdiff
path: root/src/skadns/skadnsd.c
blob: 8ccb61c7b88b0327a15888635c76dbfa1048f4e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
/* ISC license. */

#include <sys/uio.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#include <signal.h>

#include <skalibs/types.h>
#include <skalibs/error.h>
#include <skalibs/strerr2.h>
#include <skalibs/sig.h>
#include <skalibs/tai.h>
#include <skalibs/djbunix.h>
#include <skalibs/iopause.h>
#include <skalibs/textmessage.h>
#include <skalibs/textclient.h>

#include <s6-dns/s6dns.h>
#include <s6-dns/skadns.h>

typedef struct dnsio_s dnsio, *dnsio_ref ;
struct dnsio_s
{
  unsigned int xindex ;
  s6dns_engine_t dt ;
  uint16_t id ;
} ;
#define DNSIO_ZERO { .xindex = SKADNS_MAXCONCURRENCY, .dt = S6DNS_ENGINE_ZERO, .id = 0 }

static dnsio a[SKADNS_MAXCONCURRENCY] ;
static unsigned int sp = 0 ;

static void remove (unsigned int i)
{
  dnsio tmp ;
  tmp = a[sp-1] ;
  a[--sp] = a[i] ;
  a[i] = tmp ;
}

static void fail (unsigned int i)
{
  char pack[3] ;
  uint16_pack_big(pack, a[i].id) ;
  pack[2] = a[i].dt.status ;
  s6dns_engine_recycle(&a[i].dt) ;
  remove(i) ;
  if (!textmessage_put(textmessage_sender_x, pack, 3))
    strerr_diefu1sys(111, "textmessage_put") ;
}

static void answer (char c)
{
  if (!textmessage_put(textmessage_sender_1, &c, 1))
    strerr_diefu1sys(111, "textmessage_put") ;
}

static int parse_protocol (struct iovec const *v, void *context)
{
  char const *s = v->iov_base ;
  uint16_t id ;
  if (v->iov_len < 3) strerr_dief1x(100, "invalid client request") ;
  uint16_unpack_big(s, &id) ;
  switch (s[2])  /* protocol parsing */
  {
    case 'Q' : /* send a query */
    {
      tain limit ;
      uint16_t qtype ;
      if (v->iov_len < 21) strerr_dief1x(100, "invalid client request") ;
      if (sp >= SKADNS_MAXCONCURRENCY)
      {
        answer(ENFILE) ;
        break ;
      }
      uint16_unpack_big(s + 3, &qtype) ;
      if (memcmp(s + 5, "\0\0\0\0\0\0\0\0\0\0\0", 12))
        tain_unpack(s + 5, &limit) ;
      else tain_add_g(&limit, &tain_infinite_relative) ;
      if (!s6dns_engine_init_g(&a[sp].dt, &s6dns_rci_here.servers, 1, s + 17, v->iov_len - 17, qtype, &limit))
      {
        answer(errno) ;
        break ;
      }
      a[sp++].id = id ;
      answer(0) ;
      break ;
    }
    case 'q' : /* cancel a query */
    {
      unsigned int i = 0 ;
      for (; i < sp ; i++) if (a[i].id == id) break ;
      if (i >= sp)
      {
        answer(ENOENT) ;
        break ;
      }
      s6dns_engine_recycle(&a[i].dt) ;
      remove(i) ;
      answer(0) ;
      break ;
    }
    default : strerr_dief1x(100, "invalid client request") ;
  }
  (void)context ;
  return 1 ;
}

int main (void)
{
  PROG = "skadnsd" ;

  if (ndelay_on(0) < 0) strerr_diefu2sys(111, "ndelay_on ", "0") ;
  if (ndelay_on(1) < 0) strerr_diefu2sys(111, "ndelay_on ", "1") ;
  if (!sig_ignore(SIGPIPE)) strerr_diefu1sys(111, "ignore SIGPIPE") ;
  tain_now_set_stopwatch_g() ;
  if (!s6dns_init()) strerr_diefu1sys(111, "s6dns_init") ;

  {
    tain deadline ;
    tain_addsec_g(&deadline, 2) ;
    if (!textclient_server_01x_init_g(SKADNS_BANNER1, SKADNS_BANNER1_LEN, SKADNS_BANNER2, SKADNS_BANNER2_LEN, &deadline))
      strerr_diefu1sys(111, "sync with client") ;
  }
  {
    static dnsio const zero = DNSIO_ZERO ;
    unsigned int i = 0 ;
    for (; i < SKADNS_MAXCONCURRENCY ; i++) a[i] = zero ;
  }
                  
  for (;;)                
  {
    iopause_fd x[3 + sp] ;
    int r ;
    
    x[0].fd = 0 ; x[0].events = IOPAUSE_EXCEPT | IOPAUSE_READ ;
    x[1].fd = 1 ; x[1].events = IOPAUSE_EXCEPT | (textmessage_sender_isempty(textmessage_sender_1) ? 0 : IOPAUSE_WRITE) ;
    x[2].fd = textmessage_sender_fd(textmessage_sender_x) ;
    x[2].events = IOPAUSE_EXCEPT | (textmessage_sender_isempty(textmessage_sender_x) ? 0 : IOPAUSE_WRITE) ;
    {
      tain deadline = TAIN_INFINITE ;
      unsigned int i = 0 ;
      for (; i < sp ; i++)
      {
        unsigned int j = 3 + i ;
        s6dns_engine_nextdeadline(&a[i].dt, &deadline) ;
        x[j].fd = a[i].dt.fd ;
        x[j].events = 0 ;
        if (s6dns_engine_isreadable(&a[i].dt)) x[j].events |= IOPAUSE_READ ;
        if (s6dns_engine_iswritable(&a[i].dt)) x[j].events |= IOPAUSE_WRITE ;
        a[i].xindex = j ;
      }
      r = iopause_g(x, 3 + sp, &deadline) ;
    }
    if (r < 0) strerr_diefu1sys(111, "iopause") ;
    if (!r) 
    {
      unsigned int i = 0 ;
      for (; i < sp ; i++)
        if (s6dns_engine_timeout_g(&a[i].dt)) fail(i--) ;
      continue ;
    }

    if (x[1].revents & IOPAUSE_WRITE)
      if (!textmessage_sender_flush(textmessage_sender_1) && !error_isagain(errno))
        strerr_diefu1sys(111, "flush stdout") ;
    if (x[2].revents & IOPAUSE_WRITE)
      if (!textmessage_sender_flush(textmessage_sender_x) && !error_isagain(errno))
        strerr_diefu1sys(111, "flush asyncout") ;
                        
    {
      unsigned int i = 0 ;
      for (; i < sp ; i++) if (x[a[i].xindex].revents)
      {
        int r = s6dns_engine_event_g(&a[i].dt) ;
        if (r < 0) fail(i--) ;
        else if (r)
        {
          char pack[3] ;
          struct iovec v[2] = { { .iov_base = pack, .iov_len = 3 }, { .iov_base = s6dns_engine_packet(&a[i].dt), .iov_len = s6dns_engine_packetlen(&a[i].dt) } } ;
          uint16_pack_big(pack, a[i].id) ;
          pack[2] = 0 ;
          if (!textmessage_putv(textmessage_sender_x, v, 2))
            strerr_diefu1sys(111, "textmessage_put") ;
          s6dns_engine_recycle(&a[i].dt) ;
          remove(i--) ;
        }
      }
    }

    if (!textmessage_receiver_isempty(textmessage_receiver_0) || x[0].revents & IOPAUSE_READ)
    {
      if (textmessage_handle(textmessage_receiver_0, &parse_protocol, 0) < 0)
      {
        if (errno == EPIPE) break ; /* normal exit */
        strerr_diefu1sys(111, "handle messages from client") ;
      }
    }
  }
  return 0 ;
}