5fb38491e
Denys Vlasenko
2010-02-06
Subject
dnsd: fix one big-endian goof; add a TODO about RA bit
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include/platform.h+5 -0
| @@ -208,6 +208,7 @@ typedef uint32_t bb__aliased_uint32_t FIX_ALIASING; | |
| # define move_from_unaligned_int(v, intp) ((v) = *(bb__aliased_int*)(intp)) | |
| # define move_from_unaligned16(v, u16p) ((v) = *(bb__aliased_uint16_t*)(u16p)) | |
| # define move_from_unaligned32(v, u32p) ((v) = *(bb__aliased_uint32_t*)(u32p)) | |
| + | # define move_to_unaligned16(u16p, v) (*(bb__aliased_uint16_t*)(u16p) = (v)) |
| # define move_to_unaligned32(u32p, v) (*(bb__aliased_uint32_t*)(u32p) = (v)) | |
| /* #elif ... - add your favorite arch today! */ | |
| #else | |
| @@ -215,6 +216,10 @@ typedef uint32_t bb__aliased_uint32_t FIX_ALIASING; | |
| # define move_from_unaligned_int(v, intp) (memcpy(&(v), (intp), sizeof(int))) | |
| # define move_from_unaligned16(v, u16p) (memcpy(&(v), (u16p), 2)) | |
| # define move_from_unaligned32(v, u32p) (memcpy(&(v), (u32p), 4)) | |
| + | # define move_to_unaligned16(u16p, v) do { \ |
| + | uint16_t __t = (v); \ |
| + | memcpy((u16p), &__t, 4); \ |
| + | } while (0) |
| # define move_to_unaligned32(u32p, v) do { \ | |
| uint32_t __t = (v); \ | |
| memcpy((u32p), &__t, 4); \ | |
networking/dnsd.c+21 -18
| @@ -44,7 +44,7 @@ struct dns_head { | |
| uint16_t nauth; | |
| uint16_t nadd; | |
| }; | |
| - | struct dns_prop { |
| + | struct type_and_class { |
| uint16_t type; | |
| uint16_t class; | |
| }; | |
| @@ -291,7 +291,7 @@ QCLASS a two octet code that specifies the class of the query. | |
| (others are historic only) | |
| 255 any class | |
| - | 4.1.3. Resource record format |
| + | 4.1.3. Resource Record format |
| The answer, authority, and additional sections all share the same format: | |
| a variable number of resource records, where the number of records | |
| @@ -353,14 +353,14 @@ static int process_packet(struct dns_entry *conf_data, | |
| { | |
| char *answstr; | |
| struct dns_head *head; | |
| - | struct dns_prop *unaligned_qprop; |
| + | struct type_and_class *unaligned_type_class; |
| char *query_string; | |
| uint8_t *answb; | |
| uint16_t outr_rlen; | |
| uint16_t outr_flags; | |
| uint16_t type; | |
| uint16_t class; | |
| - | int querystr_len; |
| + | int query_len; |
| head = (struct dns_head *)buf; | |
| if (head->nquer == 0) { | |
| @@ -376,22 +376,22 @@ static int process_packet(struct dns_entry *conf_data, | |
| /* start of query string */ | |
| query_string = (void *)(head + 1); | |
| /* caller guarantees strlen is <= MAX_PACK_LEN */ | |
| - | querystr_len = strlen(query_string) + 1; |
| + | query_len = strlen(query_string) + 1; |
| /* may be unaligned! */ | |
| - | unaligned_qprop = (void *)(query_string + querystr_len); |
| - | querystr_len += sizeof(unaligned_qprop); |
| + | unaligned_type_class = (void *)(query_string + query_len); |
| + | query_len += sizeof(unaligned_type_class); |
| /* where to append answer block */ | |
| - | answb = (void *)(unaligned_qprop + 1); |
| + | answb = (void *)(unaligned_type_class + 1); |
| /* QR = 1 "response", RCODE = 4 "Not Implemented" */ | |
| outr_flags = htons(0x8000 | 4); | |
| - | move_from_unaligned16(type, &unaligned_qprop->type); |
| + | move_from_unaligned16(type, &unaligned_type_class->type); |
| if (type != htons(REQ_A) && type != htons(REQ_PTR)) { | |
| /* we can't handle the query type */ | |
| goto empty_packet; | |
| } | |
| - | move_from_unaligned16(class, &unaligned_qprop->class); |
| + | move_from_unaligned16(class, &unaligned_type_class->class); |
| if (class != htons(1)) { /* not class INET? */ | |
| goto empty_packet; | |
| } | |
| @@ -408,11 +408,11 @@ static int process_packet(struct dns_entry *conf_data, | |
| answstr = table_lookup(conf_data, type, query_string); | |
| outr_rlen = 4; | |
| if (answstr && type == htons(REQ_PTR)) { | |
| - | /* return a host name */ |
| + | /* returning a host name */ |
| outr_rlen = strlen(answstr) + 1; | |
| } | |
| if (!answstr | |
| - | || (unsigned)(answb - buf) + querystr_len + 4 + 2 + outr_rlen > MAX_PACK_LEN |
| + | || (unsigned)(answb - buf) + query_len + 4 + 2 + outr_rlen > MAX_PACK_LEN |
| ) { | |
| /* QR = 1 "response" | |
| * AA = 1 "Authoritative Answer" | |
| @@ -421,20 +421,23 @@ static int process_packet(struct dns_entry *conf_data, | |
| goto empty_packet; | |
| } | |
| - | /* copy query block to answer block */ |
| - | memcpy(answb, query_string, querystr_len); |
| - | answb += querystr_len; |
| - | /* append answer Resource Record */ |
| + | /* Append answer Resource Record */ |
| + | memcpy(answb, query_string, query_len); /* name, type, class */ |
| + | answb += query_len; |
| move_to_unaligned32((uint32_t *)answb, htonl(conf_ttl)); | |
| answb += 4; | |
| - | move_to_unaligned32((uint16_t *)answb, htons(outr_rlen)); |
| + | move_to_unaligned16((uint16_t *)answb, htons(outr_rlen)); |
| answb += 2; | |
| memcpy(answb, answstr, outr_rlen); | |
| answb += outr_rlen; | |
| /* QR = 1 "response", | |
| * AA = 1 "Authoritative Answer", | |
| - | * RCODE = 0 "success" */ |
| + | * TODO: need to set RA bit 0x80? One user says nslookup complains |
| + | * "Got recursion not available from SERVER, trying next server" |
| + | * "** server can't find HOSTNAME" |
| + | * RCODE = 0 "success" |
| + | */ |
| outr_flags = htons(0x8000 | 0x0400 | 0); | |
| /* we have one answer */ | |
| head->nansw = htons(1); | |