diff options
Diffstat (limited to 'dns.c')
| -rw-r--r-- | dns.c | 103 |
1 files changed, 71 insertions, 32 deletions
@@ -4,11 +4,35 @@ #include "dns.h" -flxDnsPacket* flx_dns_packet_new(void) { +flxDnsPacket* flx_dns_packet_new(guint max_size) { flxDnsPacket *p; - p = g_new(flxDnsPacket, 1); - p->size = p->rindex = 2*6; - memset(p->data, 0, p->size); + + if (max_size <= 0) + max_size = FLX_DNS_PACKET_MAX_SIZE; + else if (max_size < FLX_DNS_PACKET_HEADER_SIZE) + max_size = FLX_DNS_PACKET_HEADER_SIZE; + + p = g_malloc(sizeof(flxDnsPacket) + max_size); + p->size = p->rindex = FLX_DNS_PACKET_HEADER_SIZE; + p->max_size = max_size; + + memset(FLX_DNS_PACKET_DATA(p), 0, p->size); + return p; +} + +flxDnsPacket* flx_dns_packet_new_query(guint max_size) { + flxDnsPacket *p; + + p = flx_dns_packet_new(max_size); + flx_dns_packet_set_field(p, DNS_FIELD_FLAGS, DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)); + return p; +} + +flxDnsPacket* flx_dns_packet_new_response(guint max_size) { + flxDnsPacket *p; + + p = flx_dns_packet_new(max_size); + flx_dns_packet_set_field(p, DNS_FIELD_FLAGS, DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0)); return p; } @@ -19,30 +43,35 @@ void flx_dns_packet_free(flxDnsPacket *p) { void flx_dns_packet_set_field(flxDnsPacket *p, guint index, guint16 v) { g_assert(p); - g_assert(index < 2*6); + g_assert(index < FLX_DNS_PACKET_HEADER_SIZE); - ((guint16*) p->data)[index] = g_htons(v); + ((guint16*) FLX_DNS_PACKET_DATA(p))[index] = g_htons(v); } guint16 flx_dns_packet_get_field(flxDnsPacket *p, guint index) { g_assert(p); - g_assert(index < 2*6); + g_assert(index < FLX_DNS_PACKET_HEADER_SIZE); - return g_ntohs(((guint16*) p->data)[index]); + return g_ntohs(((guint16*) FLX_DNS_PACKET_DATA(p))[index]); } guint8* flx_dns_packet_append_name(flxDnsPacket *p, const gchar *name) { guint8 *d, *f = NULL; + guint saved_size; g_assert(p); g_assert(name); + saved_size = p->size; + for (;;) { guint n = strcspn(name, "."); if (!n || n > 63) - return NULL; + goto fail; - d = flx_dns_packet_extend(p, n+1); + if (!(d = flx_dns_packet_extend(p, n+1))) + goto fail; + if (!f) f = d; d[0] = n; @@ -61,28 +90,36 @@ guint8* flx_dns_packet_append_name(flxDnsPacket *p, const gchar *name) { break; } - d = flx_dns_packet_extend(p, 1); + if (!(d = flx_dns_packet_extend(p, 1))) + goto fail; + d[0] = 0; return f; + +fail: + p->size = saved_size; + return NULL; } guint8* flx_dns_packet_append_uint16(flxDnsPacket *p, guint16 v) { guint8 *d; - g_assert(p); - d = flx_dns_packet_extend(p, sizeof(guint16)); - *((guint16*) d) = g_htons(v); + if (!(d = flx_dns_packet_extend(p, sizeof(guint16)))) + return NULL; + *((guint16*) d) = g_htons(v); return d; } guint8 *flx_dns_packet_append_uint32(flxDnsPacket *p, guint32 v) { guint8 *d; - g_assert(p); - d = flx_dns_packet_extend(p, sizeof(guint32)); + + if (!(d = flx_dns_packet_extend(p, sizeof(guint32)))) + return NULL; + *((guint32*) d) = g_htonl(v); return d; @@ -95,21 +132,22 @@ guint8 *flx_dns_packet_append_bytes(flxDnsPacket *p, gconstpointer b, guint l) g_assert(b); g_assert(l); - d = flx_dns_packet_extend(p, l); - g_assert(d); - memcpy(d, b, l); + if (!(d = flx_dns_packet_extend(p, l))) + return NULL; + memcpy(d, b, l); return d; } - guint8 *flx_dns_packet_extend(flxDnsPacket *p, guint l) { guint8 *d; g_assert(p); - g_assert(p->size+l <= sizeof(p->data)); - d = p->data + p->size; + if (p->size+l > p->max_size) + return NULL; + + d = FLX_DNS_PACKET_DATA(p) + p->size; p->size += l; return d; @@ -123,13 +161,14 @@ guint8 *flx_dns_packet_append_name_compressed(flxDnsPacket *p, const gchar *name if (!prev) return flx_dns_packet_append_name(p, name); - k = prev - p->data; + k = prev - FLX_DNS_PACKET_DATA(p); if (k < 0 || k >= 0x4000 || (guint) k >= p->size) return flx_dns_packet_append_name(p, name); - d = (guint16*) flx_dns_packet_extend(p, sizeof(guint16)); - *d = g_htons((0xC000 | k)); + if (!(d = (guint16*) flx_dns_packet_extend(p, sizeof(guint16)))) + return NULL; + *d = g_htons((0xC000 | k)); return prev; } @@ -166,7 +205,7 @@ static gint consume_labels(flxDnsPacket *p, guint index, gchar *ret_name, guint if (index+1 > p->size) return -1; - n = p->data[index]; + n = FLX_DNS_PACKET_DATA(p)[index]; if (!n) { index++; @@ -197,7 +236,7 @@ static gint consume_labels(flxDnsPacket *p, guint index, gchar *ret_name, guint } else first_label = 0; - memcpy(ret_name, p->data + index, n); + memcpy(ret_name, FLX_DNS_PACKET_DATA(p) + index, n); index += n; ret_name += n; l -= n; @@ -210,7 +249,7 @@ static gint consume_labels(flxDnsPacket *p, guint index, gchar *ret_name, guint if (index+2 > p->size) return -1; - index = ((guint) (p->data[index] & ~0xC0)) << 8 | p->data[index+1]; + index = ((guint) (FLX_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | FLX_DNS_PACKET_DATA(p)[index+1]; if (!compressed) ret += 2; @@ -238,7 +277,7 @@ gint flx_dns_packet_consume_uint16(flxDnsPacket *p, guint16 *ret_v) { if (p->rindex + sizeof(guint16) > p->size) return -1; - *ret_v = g_ntohs(*((guint16*) (p->data + p->rindex))); + *ret_v = g_ntohs(*((guint16*) (FLX_DNS_PACKET_DATA(p) + p->rindex))); p->rindex += sizeof(guint16); return 0; @@ -251,7 +290,7 @@ gint flx_dns_packet_consume_uint32(flxDnsPacket *p, guint32 *ret_v) { if (p->rindex + sizeof(guint32) > p->size) return -1; - *ret_v = g_ntohl(*((guint32*) (p->data + p->rindex))); + *ret_v = g_ntohl(*((guint32*) (FLX_DNS_PACKET_DATA(p) + p->rindex))); p->rindex += sizeof(guint32); return 0; @@ -265,7 +304,7 @@ gint flx_dns_packet_consume_bytes(flxDnsPacket *p, gpointer ret_data, guint l) { if (p->rindex + l > p->size) return -1; - memcpy(ret_data, p->data + p->rindex, l); + memcpy(ret_data, FLX_DNS_PACKET_DATA(p) + p->rindex, l); p->rindex += l; return 0; @@ -277,7 +316,7 @@ gconstpointer flx_dns_packet_get_rptr(flxDnsPacket *p) { if (p->rindex >= p->size) return NULL; - return p->data + p->rindex; + return FLX_DNS_PACKET_DATA(p) + p->rindex; } gint flx_dns_packet_skip(flxDnsPacket *p, guint length) { |