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author | Denis Vlasenko <vda.linux@googlemail.com> | 2009-04-12 19:03:01 +0000 |
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committer | Denis Vlasenko <vda.linux@googlemail.com> | 2009-04-12 19:03:01 +0000 |
commit | ef1b439669f7f952633eea3879defb357224eb4c (patch) | |
tree | b8170a8246d754661934927b82cb7090c4653e0c | |
parent | e12c90217b8de612d2dfa429a71ad458b1754cf1 (diff) | |
download | busybox-w32-ef1b439669f7f952633eea3879defb357224eb4c.tar.gz busybox-w32-ef1b439669f7f952633eea3879defb357224eb4c.tar.bz2 busybox-w32-ef1b439669f7f952633eea3879defb357224eb4c.zip |
dnsd: stop using oversized buffer. trim comment.
-rw-r--r-- | networking/dnsd.c | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/networking/dnsd.c b/networking/dnsd.c index 5dbaec1eb..56ede3fca 100644 --- a/networking/dnsd.c +++ b/networking/dnsd.c | |||
@@ -24,15 +24,10 @@ | |||
24 | #define DEBUG 0 | 24 | #define DEBUG 0 |
25 | 25 | ||
26 | enum { | 26 | enum { |
27 | /* Can tweak this */ | 27 | /* can tweak this */ |
28 | DEFAULT_TTL = 120, | 28 | DEFAULT_TTL = 120, |
29 | 29 | ||
30 | /* Cannot get bigger packets than 512 per RFC1035. | 30 | /* cannot get bigger packets than 512 per RFC1035. */ |
31 | * In practice this can be set considerably smaller: | ||
32 | * Length of response packet is header (12B) + 2*type(4B) + 2*class(4B) + | ||
33 | * ttl(4B) + rlen(2B) + r (MAX_NAME_LEN = 21B) + | ||
34 | * 2*querystring (2 MAX_NAME_LEN = 42B), all together 90 Bytes | ||
35 | */ | ||
36 | MAX_PACK_LEN = 512, | 31 | MAX_PACK_LEN = 512, |
37 | IP_STRING_LEN = sizeof(".xxx.xxx.xxx.xxx"), | 32 | IP_STRING_LEN = sizeof(".xxx.xxx.xxx.xxx"), |
38 | MAX_NAME_LEN = IP_STRING_LEN - 1 + sizeof(".in-addr.arpa"), | 33 | MAX_NAME_LEN = IP_STRING_LEN - 1 + sizeof(".in-addr.arpa"), |
@@ -225,9 +220,9 @@ OPCODE 0 standard query (QUERY) | |||
225 | 2 server status request (STATUS) | 220 | 2 server status request (STATUS) |
226 | AA Authoritative Answer - this bit is valid in responses. | 221 | AA Authoritative Answer - this bit is valid in responses. |
227 | Responding name server is an authority for the domain name | 222 | Responding name server is an authority for the domain name |
228 | in question section. Answer section may have multiple owner names | 223 | in question section. Answer section may have multiple owner names |
229 | because of aliases. The AA bit corresponds to the name which matches | 224 | because of aliases. The AA bit corresponds to the name which matches |
230 | the query name, or the first owner name in the answer section. | 225 | the query name, or the first owner name in the answer section. |
231 | TC TrunCation - this message was truncated. | 226 | TC TrunCation - this message was truncated. |
232 | RD Recursion Desired - this bit may be set in a query and | 227 | RD Recursion Desired - this bit may be set in a query and |
233 | is copied into the response. If RD is set, it directs | 228 | is copied into the response. If RD is set, it directs |
@@ -240,10 +235,10 @@ RCODE Response code. | |||
240 | 0 No error condition | 235 | 0 No error condition |
241 | 1 Format error | 236 | 1 Format error |
242 | 2 Server failure - server was unable to process the query | 237 | 2 Server failure - server was unable to process the query |
243 | due to a problem with the name server. | 238 | due to a problem with the name server. |
244 | 3 Name Error - meaningful only for responses from | 239 | 3 Name Error - meaningful only for responses from |
245 | an authoritative name server. The referenced domain name | 240 | an authoritative name server. The referenced domain name |
246 | does not exist. | 241 | does not exist. |
247 | 4 Not Implemented. | 242 | 4 Not Implemented. |
248 | 5 Refused. | 243 | 5 Refused. |
249 | QDCOUNT number of entries in the question section. | 244 | QDCOUNT number of entries in the question section. |
@@ -293,7 +288,7 @@ QTYPE a two octet type of the query. | |||
293 | 255 a request for all records | 288 | 255 a request for all records |
294 | QCLASS a two octet code that specifies the class of the query. | 289 | QCLASS a two octet code that specifies the class of the query. |
295 | 1 the Internet | 290 | 1 the Internet |
296 | (others are historic only) | 291 | (others are historic only) |
297 | 255 any class | 292 | 255 any class |
298 | 293 | ||
299 | 4.1.3. Resource record format | 294 | 4.1.3. Resource record format |
@@ -464,9 +459,7 @@ int dnsd_main(int argc UNUSED_PARAM, char **argv) | |||
464 | unsigned lsa_size; | 459 | unsigned lsa_size; |
465 | int udps, opts; | 460 | int udps, opts; |
466 | uint16_t port = 53; | 461 | uint16_t port = 53; |
467 | /* Paranoid sizing: querystring x2 + ttl + outr_rlen + answstr */ | 462 | uint8_t buf[MAX_PACK_LEN + 1]; |
468 | /* I'd rather see process_packet() fixed instead... */ | ||
469 | uint8_t buf[MAX_PACK_LEN * 2 + 4 + 2 + (MAX_NAME_LEN+1)]; | ||
470 | 463 | ||
471 | opts = getopt32(argv, "vi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport); | 464 | opts = getopt32(argv, "vi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport); |
472 | //if (opts & 0x1) // -v | 465 | //if (opts & 0x1) // -v |