diff options
Diffstat (limited to 'src/packet/packet.c')
| -rw-r--r-- | src/packet/packet.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/src/packet/packet.c b/src/packet/packet.c new file mode 100644 index 0000000..83dc5c3 --- /dev/null +++ b/src/packet/packet.c @@ -0,0 +1,184 @@ +#include <stdbool.h> +#include <stdio.h> +#include <string.h> +#include <stdlib.h> + +#include "packet.h" +#include "buffer.h" +#include "header.h" +#include "question.h" +#include "record.h" + +void read_packet(PacketBuffer* buffer, Packet* packet) { + read_header(buffer, &packet->header); + + packet->questions = malloc(sizeof(Question) * packet->header.questions); + for(uint16_t i = 0; i < packet->header.questions; i++) { + if (!read_question(buffer, &packet->questions[i])) { + i--; + packet->header.questions--; + } + } + + packet->answers = malloc(sizeof(Record) * packet->header.answers); + for(uint16_t i = 0; i < packet->header.answers; i++) { + if (!read_record(buffer, &packet->answers[i])) { + i--; + packet->header.answers--; + } + } + + packet->authorities = malloc(sizeof(Record) * packet->header.authoritative_entries); + for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) { + if (!read_record(buffer, &packet->authorities[i])) { + i--; + packet->header.authoritative_entries--; + } + } + + packet->resources = malloc(sizeof(Record) * packet->header.resource_entries); + for(uint16_t i = 0; i < packet->header.resource_entries; i++) { + if (!read_record(buffer, &packet->resources[i])) { + i--; + packet->header.resource_entries--; + } + } +} + +void write_packet(PacketBuffer* buffer, Packet* packet) { + write_header(buffer, &packet->header); + + for(uint16_t i = 0; i < packet->header.questions; i++) { + write_question(buffer, &packet->questions[i]); + } + + for(uint16_t i = 0; i < packet->header.answers; i++) { + write_record(buffer, &packet->answers[i]); + } + + for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) { + write_record(buffer, &packet->authorities[i]); + } + + for(uint16_t i = 0; i < packet->header.resource_entries; i++) { + write_record(buffer, &packet->resources[i]); + } +} + +void free_packet(Packet* packet) { + + for(uint16_t i = 0; i < packet->header.questions; i++) { + free_question(&packet->questions[i]); + } + free(packet->questions); + + for(uint16_t i = 0; i < packet->header.answers; i++) { + free_record(&packet->answers[i]); + } + free(packet->answers); + + for(uint16_t i = 0; i < packet->header.authoritative_entries; i++) { + free_record(&packet->authorities[i]); + } + free(packet->authorities); + + for(uint16_t i = 0; i < packet->header.resource_entries; i++) { + free_record(&packet->resources[i]); + } + free(packet->resources); +} + +bool get_random_a(Packet* packet, IpAddr* addr) { + for (uint16_t i = 0; i < packet->header.answers; i++) { + Record record = packet->answers[i]; + if (record.type == A) { + create_ip_addr(record.data.a.addr, addr); + return true; + } else if (record.type == AAAA) { + create_ip_addr6(record.data.aaaa.addr, addr); + return true; + } + } + return false; +} + +static bool ends_with(uint8_t* full, uint8_t* end) { + uint8_t check = end[0]; + uint8_t len = full[0]; + + if (check > len) { + return false; + } + + for(uint8_t i = 0; i < check; i++) { + if (end[check - 1 - i] != full[len - 1 - i]) { + return false; + } + } + + return true; +} + +static bool equals(uint8_t* a, uint8_t* b) { + if (a[0] != b[0]) { + return false; + } + + for(uint8_t i = 1; i < a[0] + 1; i++) { + if(a[i] != b[i]) { + return false; + } + } + + return true; +} + +bool get_resolved_ns(Packet* packet, uint8_t* qname, IpAddr* addr) { + for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) { + Record record = packet->authorities[i]; + if (record.type != NS) { + continue; + } + + if(!ends_with(qname, record.domain)) { + continue; + } + + for (uint16_t i = 0; i < packet->header.resource_entries; i++) { + Record resource = packet->resources[i]; + if (!equals(record.data.ns.host, resource.domain)) { + continue; + } + + if (resource.type == A) { + create_ip_addr(record.data.a.addr, addr); + return true; + } else if (resource.type == AAAA) { + create_ip_addr6(record.data.aaaa.addr, addr); + return true; + } + } + } + return false; +} + +bool get_unresoled_ns(Packet* packet, uint8_t* qname, Question* question) { + for (uint16_t i = 0; i < packet->header.authoritative_entries; i++) { + Record record = packet->authorities[i]; + if (record.type != NS) { + continue; + } + + if(!ends_with(qname, record.domain)) { + continue; + } + + uint8_t* host = record.data.ns.host; + + question->qtype = NS; + question->domain = malloc(host[0] + 1); + memcpy(question->domain, host, host[0] + 1); + return true; + } + return false; +} |