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-rw-r--r--src/main.c498
-rw-r--r--src/proto.c519
-rw-r--r--src/proto.h44
-rw-r--r--src/routing.c64
-rw-r--r--src/routing.h3
5 files changed, 644 insertions, 484 deletions
diff --git a/src/main.c b/src/main.c
index df6080d..f81d289 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,491 +1,51 @@
-#include "routing.h"
-#include "benc.h"
-#include "query.h"
+#include "proto.h"
#include "log.h"
-#include <errno.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <ctype.h>
-#include <assert.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <limits.h>
-#include <unistd.h>
-#include <stdbool.h>
-#include <string.h>
-#include <sys/socket.h>
-#include <netdb.h>
-#include <arpa/inet.h>
-#include <netdb.h>
-#include <sys/types.h>
-#include <stdio.h>
-
-#define MAX(a, b) \
- ({ \
- __typeof__ (a) _a = (a); \
- __typeof__ (b) _b = (b); \
- _a > _b ? _a : _b; \
- })
-
-#define MIN(a, b) \
- ({ \
- __typeof__ (a) _a = (a); \
- __typeof__ (b) _b = (b); \
- _a < _b ? _a : _b; \
- })
-
-
-void dbgl_id(struct nodeid* id) {
- for(uint8_t i = 0; i < 5; i++) {
- fprintf(stderr, "0x%08x ", id->inner[i]);
- }
- fprintf(stderr, "\n");
- fflush(stderr);
-}
-
-struct discovery {
- uint16_t port;
- struct nodeid expected_id;
-};
-
-int sockaddr_cmp(struct sockaddr* x, struct sockaddr* y) {
-#define CMP(a, b) \
- do { \
- typeof(a) cmp = a - b; \
- if(cmp != 0) return cmp; \
- } while(0)
- if (x->sa_family == AF_INET) {
- struct sockaddr_in *xin = (void*)x;
- struct sockaddr_in *yin = (void*)y;
-
- CMP(ntohl(xin->sin_addr.s_addr), ntohl(yin->sin_addr.s_addr));
- CMP(ntohs(xin->sin_port), ntohs(yin->sin_port));
- } else if (x->sa_family == AF_INET6) {
- struct sockaddr_in6 *xin6 = (void*)x, *yin6 = (void*)y;
- int r = memcmp(xin6->sin6_addr.s6_addr, yin6->sin6_addr.s6_addr, sizeof(xin6->sin6_addr.s6_addr));
- if (r != 0)
- return r;
- CMP(ntohs(xin6->sin6_port), ntohs(yin6->sin6_port));
- CMP(xin6->sin6_flowinfo, yin6->sin6_flowinfo);
- CMP(xin6->sin6_scope_id, yin6->sin6_scope_id);
- } else {
- err("Unsupported sa_family");
- abort();
- }
-
- return 0;
-};
-
-#define UNDEF_ADDR (struct in_addr){0xC0000200}
-#define MAX_DISC 32
-struct in_addr addrs[MAX_DISC];
-struct discovery pending_discover[MAX_DISC];
-
-typedef void (*cont)(struct nodeid* self, char* packet, size_t packet_len, int socket, struct sockaddr_in* remote, socklen_t remote_len);
-
-#define MAX_INFLIGHT 32
-bool reqalloc[MAX_INFLIGHT] = { false };
-struct {
- struct sockaddr addr;
- cont fun;
-} requestdata[MAX_INFLIGHT];
-
-bool alloc_req(uint16_t* reqId) {
- for(size_t i = 0; i < MAX_INFLIGHT; i++) {
- if(!reqalloc[i]) {
- reqalloc[i] = true;
- *reqId = i;
- return true;
- }
- }
- return false;
-}
-
-bool find_req(uint32_t transId, uint16_t* reqId) {
- *reqId = transId;
- return reqalloc[transId];
-}
-
-void getclient_response(struct nodeid* self, char* packet, size_t packet_len, int socket, struct sockaddr_in* remote, socklen_t remote_len);
-
-uint8_t rand_byte() {
- int limit = RAND_MAX - (RAND_MAX % UINT8_MAX);
- int val;
- while((val = rand()) > limit);
-
- return val;
-}
-
-int send_ping(struct nodeid* self, const int sfd, const struct sockaddr* dest_addr, socklen_t dest_len) {
- // Generate a random target
- struct nodeid target;
- for(uint8_t *target_byte = (uint8_t*)&target; target_byte < ((uint8_t*)&target)+sizeof(target); target_byte++) {
- *target_byte = rand_byte();
- }
-
- uint16_t reqId;
- if(!alloc_req(&reqId)) {
- return ENOBUFS;
- }
- char buff[128];
- size_t i = 0;
-
- dbg("Allocating request %d", reqId);
- requestdata[reqId].fun = &getclient_response;
- requestdata[reqId].addr = *dest_addr;
-
- int rc = snprintf(buff+i, 128-i, "d1:ad2:id20:");
- if(rc < 0)
- return EPERM;
- i += rc;
- memcpy(buff+i, self, sizeof(struct nodeid));
- i += sizeof(struct nodeid);
- rc = snprintf(buff+i, 128-i, "6:target20:");
- if(rc < 0)
- return EPERM;
- i += rc;
- memcpy(buff+i, &target, sizeof(struct nodeid));
- i += sizeof(struct nodeid);
- rc = snprintf(buff+i, 128-i, "e1:q9:find_node1:t%d:%d1:y1:qe", (reqId/10)+1, reqId);
- if(rc < 0)
- return EPERM;
- i += rc;
-
- //now reply the client with the same data
- rc = sendto(sfd, buff, i, 0, dest_addr, dest_len);
- if (rc == -1) {
- return EPERM; // Operation not permitted is used as the default "generic" error
- }
-
- return 0;
-}
-
-void getclient_response(struct nodeid* self, char* packet, size_t packet_len, int socket, struct sockaddr_in* remote, socklen_t remote_len) {
- struct benc_node stream[256];
- struct bcursor bcursor;
- bcur_open(&bcursor, packet, packet+packet_len, stream, 256);
-
- if(bcursor.end - bcursor.readhead <= 0) {
- err("Reponse too short");
- exit(EXIT_FAILURE);
- }
-
- struct nodeid id;
- uint8_t nodes_len;
- struct nodeid nodes[8];
- struct in_addr ips[8];
- uint16_t ports[8];
-
-
- // Read the payload
- {
- // Check that we have a dict
- if(bcursor.readhead->type != BNT_DICT) {
- err("Response is not a dict");
- exit(EXIT_FAILURE);
- }
- bcur_next(&bcursor, 1);
-
- bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING}, (const char*[]){"r"}, (const size_t[]){1}, 1);
- // Skip the key
- bcur_next(&bcursor, 1);
-
- if(bcursor.readhead->type != BNT_DICT) {
- err("Wrong value type for response");
- exit(EXIT_FAILURE);
- }
-
- // Skip the dict element
- bcur_next(&bcursor, 1);
-
- while(bcursor.readhead->type != BNT_END) {
- switch(bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING, BNT_STRING}, (const char*[]){"nodes", "id"}, (const size_t[]){5, 2}, 2)) {
- case 0:
- // Skip the key
- bcur_next(&bcursor, 1);
-
- if(bcursor.readhead->type != BNT_STRING) {
- err("Wrong value type for response");
- exit(EXIT_FAILURE);
- }
-
- if((bcursor.readhead->size % 26) != 0) {
- err("get_nodes call returned an incorrect nodes array");
- exit(EXIT_FAILURE);
- }
-
- nodes_len = MIN(bcursor.readhead->size/26, 8);
- dbg("We have %d (%d/26) nodes", nodes_len, bcursor.readhead->size);
- for(int i = 0; i < nodes_len; i++) {
- memcpy(nodes+i, bcursor.readhead->loc+(26*i), 20);
- memcpy(ips+i, bcursor.readhead->loc+(26*i)+20, 4);
- memcpy(ports+i, bcursor.readhead->loc+(26*i)+24, 2);
- }
-
- // Skip the value
- bcur_next(&bcursor, 1);
- break;
- case 1:
- // Skip the key
- bcur_next(&bcursor, 1);
-
- if(bcursor.readhead->type != BNT_STRING) {
- err("Wrong value type for response");
- exit(EXIT_FAILURE);
- }
-
- if(bcursor.readhead->size != 20) {
- err("remote node id was not 20 bytes long");
- exit(EXIT_FAILURE);
- }
-
- memcpy(&id, bcursor.readhead->loc, 20);
-
- // Skip the value
- bcur_next(&bcursor, 1);
- break;
- }
+void flush_messages(int sfd, struct message* cursor, const struct message* const end) {
+ dbg("Flushing %ld pending messages", end - cursor);
+ for(; cursor < end; cursor++) {
+ //now reply the client with the same data
+ int rc = sendto(sfd, cursor->payload, cursor->payload_len, 0, (const struct sockaddr*)&cursor->dest, cursor->dest_len);
+ if (rc < 0) {
+ fatal("Failed to send message");
}
}
-
- // Print the candidates
- for(uint8_t i = 0; i < nodes_len; i++) {
- dbgl_id(&nodes[i]);
- printf("Candidate %s:%d\n", inet_ntoa(ips[i]), ntohs(ports[i]));
-
- struct sockaddr_in dest = {
- .sin_family = AF_INET,
- .sin_addr = ips[i],
- .sin_port = ports[i],
- };
-
- if(routing_interested(&nodes[i])) {
- int rc = send_ping(self, socket, (struct sockaddr*)&dest, sizeof(struct sockaddr_in));
- if(rc != 0) {
- err("send_ping failed %d", rc);
- }
- } else {
- dbg("Not interested in node");
- }
- }
-
- struct entry* entry;
- routing_offer(&id, &entry);
}
-enum commandType {
- CT_QUERY,
- CT_RESPONSE,
- CT_ERROR,
-};
-
int main(int argc, char** argv) {
- for(int i = 0; i < MAX_DISC; i++) {
- // 192.0.2.0
- addrs[i] = UNDEF_ADDR;
- }
-
- struct nodeid self = {.inner={0x0034048f, 0x08000020, 0x00888880, 0x02008460, 0x0ab00521}};
- routing_init(&self);
- dbgl_id(&self);
-
- int sfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
- if(sfd == -1) {
- err("Failed creating socket");
- exit(1);
- }
- struct sockaddr_in bindAddr = {0};
- bindAddr.sin_family = AF_INET;
- bindAddr.sin_port = htons(6881);
- bindAddr.sin_addr.s_addr = htonl(INADDR_ANY);
- bind(sfd, (struct sockaddr*)&bindAddr, sizeof(struct sockaddr_in));
-
- struct addrinfo hints = {0};
- hints.ai_family = AF_INET;
- hints.ai_socktype = SOCK_DGRAM;
- hints.ai_protocol = IPPROTO_UDP;
- hints.ai_flags = AI_NUMERICSERV;
+ struct message outbuff[10] = {0};
- struct addrinfo* res;
- int rc = getaddrinfo("router.bittorrent.com", "6881", &hints, &res);
- if(rc != 0) {
- err("Failed getting the bootstrap ip: %s", gai_strerror(rc));
- exit(EXIT_FAILURE);
- }
-
- for(struct addrinfo* cur = res; cur != NULL; cur = cur->ai_next) {
- char buff[128];
- inet_ntop(cur->ai_family, &((struct sockaddr_in*)cur->ai_addr)->sin_addr, buff, 128);
- dbg("IP %s", buff);
-
- /* size_t i = 0; */
- /* int rc = snprintf(buff+i, 128-i, "d1:ad2:id20:"); */
- /* i += rc; */
- /* memcpy(buff+i, &self, sizeof(struct nodeid)); */
- /* i += sizeof(struct nodeid); */
- /* rc = snprintf(buff+i, 128-i, "e1:q4:ping1:t2:ab1:y1:qe"); */
- /* i += rc; */
+ struct dht dht;
+ dht.self = (struct nodeid){.inner={0x0034048f, 0x08000020, 0x00888880, 0x02008460, 0x0ab00521}};
+ struct message* message_cursor = outbuff;
+ proto_begin(&dht, &message_cursor, outbuff+10);
+ flush_messages(dht.sfd, outbuff, message_cursor);
- send_ping(&self, sfd, cur->ai_addr, cur->ai_addrlen);
- }
-
- freeaddrinfo(res);
- //keep listening for data
- while(1) {
+ int rc = 0;
+ while(rc == 0) {
char buff[2049];
printf("Waiting for data...");
fflush(stdout);
-
- //try to receive some data, this is a blocking call
- ssize_t recv_len;
- struct sockaddr_in remote;
+
+ // Try to receive some data, this is a blocking call
+ struct sockaddr_storage remote;
socklen_t remote_len = sizeof(remote);
- if ((recv_len = recvfrom(sfd, buff, 2048, 0, (struct sockaddr *)&remote, &remote_len)) == -1) {
- fatal("recvfrom failed");
- }
- if(recv_len >= 2048) {
- fatal("Recv buffer too small");
+ ssize_t recv_len = recvfrom(dht.sfd, buff, 2048, 0, (struct sockaddr *)&remote, &remote_len);
+ if(recv_len == -1) {
+ fatal("RECV failed");
+ } else if(recv_len >= 2048) {
+ fatal("Receive buffer too small");
}
// Null terminate the packet
buff[recv_len] = '\0';
- printf("Received packet from %s:%d\n", inet_ntoa(remote.sin_addr), ntohs(remote.sin_port));
-
- struct bcursor bcursor;
- struct benc_node stream[256];
- bcur_open(&bcursor, buff, buff+recv_len, stream, 256);
- benc_print(bcursor.readhead, bcursor.end - bcursor.readhead);
-
- if(bcursor.readhead->type != BNT_DICT) {
- fatal("First value is not a dict");
- }
- bcur_next(&bcursor, 1);
-
- bool discard = false;
- enum commandType type;
- bool transaction_set = false;
- char transaction[64];
- size_t transaction_len;
- bool query_set = false;
- char query[64];
- size_t query_len;
- while(bcursor.readhead->type != BNT_END) {
- switch(bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING, BNT_STRING, BNT_STRING}, (const char*[]){"y", "t", "q"}, (const size_t[]){1, 1, 1}, 3)) {
- case 0:
- // Skip the key
- bcur_next(&bcursor, 1);
- if(*bcursor.readhead->loc == 'r') {
- type = CT_RESPONSE;
- } else if(*bcursor.readhead->loc == 'q') {
- type = CT_QUERY;
- } else if(*bcursor.readhead->loc == 'e') {
- type = CT_ERROR;
- } else {
- fatal("Unknown command type %c", *bcursor.readhead->loc);
- }
- // Skip the value
- bcur_next(&bcursor, 1);
- break;
- case 1: {
- // Skip the key
- bcur_next(&bcursor, 1);
- if(bcursor.readhead->size > 64-1)
- fatal("Transaction string too long");
-
- transaction_set = true;
- transaction_len = bcursor.readhead->size;
- memcpy(transaction, bcursor.readhead->loc, transaction_len);
- transaction[transaction_len] = '\0';
-
- // Skip the value
- bcur_next(&bcursor, 1);
- break;
- }
- case 2: {
- bcur_next(&bcursor, 1);
- query_set = true;
- query_len = bcursor.readhead->size;
- memcpy(query, bcursor.readhead->loc, query_len);
- query[query_len] = '\0';
- bcur_next(&bcursor, 1);
- }
- }
- }
-
- if(discard)
- continue;
-
- if(type == CT_RESPONSE) {
- uint32_t transaction_number;
-
- if(!transaction_set)
- fatal("No transaction in response");
-
- // Temporary null terminate the string to parse the number without a copy
- char* end;
- transaction_number = strtol(transaction, &end, 10);
-
- if(end != transaction+transaction_len) {
- fatal("DISCARD: Transaction id is not a number %.*s", transaction_len, transaction);
- }
-
- uint16_t reqId;
- if(!find_req(transaction_number, &reqId)) {
- dbg("DISCARD: unknown transaction id %d", transaction);
- continue;
- }
- dbg("Transaction id matches request %d", reqId);
-
- if(sockaddr_cmp(&requestdata[reqId].addr, (struct sockaddr*)&remote) != 0) {
- fatal("Unexpected IP for valid transaction");
- }
-
- requestdata[reqId].fun(&self, buff, recv_len, sfd, &remote, remote_len);
-
- reqalloc[reqId] = false;
- } else if(type == CT_QUERY) { // Must be a query
- if(!query_set)
- fatal("No query function in query request");
- if(!transaction_set)
- fatal("No transaction in request");
-
- assert(strlen(query) == query_len);
-
- char response[1024];
- char* end = response+sizeof(response)-1;
- char* cursor = response;
-
- int rc = snprintf(cursor, end-cursor , "d1:t%ld:", transaction_len);
- if(rc < 0)
- return EPERM;
- cursor += rc;
- memcpy(cursor, transaction, transaction_len);
- cursor += transaction_len;
- rc = snprintf(cursor, end-cursor, "1:y1:r1:r");
- if(rc < 0)
- return EPERM;
- cursor += rc;
-
- rc = handle_request(&self, query, buff, recv_len, &cursor, end-cursor-1);
- if(rc != 0) fatal("Error handling request");
-
- rc = snprintf(cursor, end-cursor, "e");
- if(rc < 0)
- return EPERM;
- cursor += rc;
-
- //now reply the client with the same data
- rc = sendto(sfd, buff, cursor-response, 0, (const struct sockaddr*)&remote, remote_len);
- if (rc == -1) {
- return EPERM; // Operation not permitted is used as the default "generic" error
- }
-
- }
+ struct message* message_cursor = outbuff;
+ rc = proto_run(&dht, buff, recv_len, (struct sockaddr_in*)&remote, remote_len, &message_cursor, outbuff+10);
+ flush_messages(dht.sfd, outbuff, message_cursor);
}
- close(sfd);
+ proto_end(&dht);
- return 0;
+ return rc;
}
diff --git a/src/proto.c b/src/proto.c
new file mode 100644
index 0000000..7a7eb73
--- /dev/null
+++ b/src/proto.c
@@ -0,0 +1,519 @@
+#include "proto.h"
+
+#include "benc.h"
+#include "query.h"
+#include "log.h"
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <math.h>
+#include <stdint.h>
+#include <limits.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <string.h>
+#include <netdb.h>
+#include <netdb.h>
+#include <sys/types.h>
+#include <stdio.h>
+
+#define MAX(a, b) \
+ ({ \
+ __typeof__ (a) _a = (a); \
+ __typeof__ (b) _b = (b); \
+ _a > _b ? _a : _b; \
+ })
+
+#define MIN(a, b) \
+ ({ \
+ __typeof__ (a) _a = (a); \
+ __typeof__ (b) _b = (b); \
+ _a < _b ? _a : _b; \
+ })
+
+#define UNCERTAIN_TIME 10
+
+
+void dbgl_id(struct nodeid* id) {
+ for(uint8_t i = 0; i < 5; i++) {
+ fprintf(stderr, "0x%08x ", id->inner[i]);
+ }
+ fprintf(stderr, "\n");
+ fflush(stderr);
+}
+
+int sockaddr_cmp(struct sockaddr* x, struct sockaddr* y) {
+#define CMP(a, b) \
+ do { \
+ typeof(a) cmp = a - b; \
+ if(cmp != 0) return cmp; \
+ } while(0)
+ if (x->sa_family == AF_INET) {
+ struct sockaddr_in *xin = (void*)x;
+ struct sockaddr_in *yin = (void*)y;
+
+ CMP(ntohl(xin->sin_addr.s_addr), ntohl(yin->sin_addr.s_addr));
+ CMP(ntohs(xin->sin_port), ntohs(yin->sin_port));
+ } else if (x->sa_family == AF_INET6) {
+ struct sockaddr_in6 *xin6 = (void*)x, *yin6 = (void*)y;
+ int r = memcmp(xin6->sin6_addr.s6_addr, yin6->sin6_addr.s6_addr, sizeof(xin6->sin6_addr.s6_addr));
+ if (r != 0)
+ return r;
+ CMP(ntohs(xin6->sin6_port), ntohs(yin6->sin6_port));
+ CMP(xin6->sin6_flowinfo, yin6->sin6_flowinfo);
+ CMP(xin6->sin6_scope_id, yin6->sin6_scope_id);
+ } else {
+ err("Unsupported sa_family");
+ abort();
+ }
+
+ return 0;
+};
+
+bool alloc_req(struct dht* dht, uint16_t* reqId) {
+ for(size_t i = 0; i < MAX_INFLIGHT; i++) {
+ if(!dht->reqalloc[i]) {
+ dht->reqalloc[i] = true;
+ *reqId = i;
+ return true;
+ }
+ }
+ return false;
+}
+
+bool find_req(struct dht* dht, uint32_t transId, uint16_t* reqId) {
+ *reqId = transId;
+ return dht->reqalloc[transId];
+}
+
+struct msgbuff {
+ struct message** messages;
+ const struct message* const messages_end;
+};
+
+void getclient_response(struct dht* dht, struct nodeid* self, char* packet, size_t packet_len, int socket, struct sockaddr* remote, socklen_t remote_len, struct msgbuff* msgbuff);
+
+uint8_t rand_byte() {
+ int limit = RAND_MAX - (RAND_MAX % UINT8_MAX);
+ int val;
+ while((val = rand()) > limit);
+
+ return val;
+}
+
+int send_ping(struct dht* dht, struct nodeid* self, const int sfd, const struct sockaddr* dest_addr, socklen_t dest_len, struct msgbuff* msgbuff) {
+ // Generate a random target
+ struct nodeid target;
+ for(uint8_t *target_byte = (uint8_t*)&target; target_byte < ((uint8_t*)&target)+sizeof(target); target_byte++) {
+ *target_byte = rand_byte();
+ }
+
+ uint16_t reqId;
+ if(!alloc_req(dht, &reqId)) {
+ return ENOBUFS;
+ }
+
+ assert(*msgbuff->messages < msgbuff->messages_end);
+ struct message* message = *msgbuff->messages;
+
+ memcpy(&message->dest, dest_addr, dest_len);
+ message->dest_len = dest_len;
+ char* buff = message->payload;
+ size_t i = 0;
+
+ dbg("Allocating request %d", reqId);
+ dht->requestdata[reqId].fun = &getclient_response;
+ memcpy(&dht->requestdata[reqId].addr, dest_addr, dest_len);
+
+ int rc = snprintf(buff+i, 128-i, "d1:ad2:id20:");
+ if(rc < 0)
+ fatal("Failed to write packet");
+ i += rc;
+ memcpy(buff+i, self, sizeof(struct nodeid));
+ i += sizeof(struct nodeid);
+ rc = snprintf(buff+i, 128-i, "6:target20:");
+ if(rc < 0)
+ fatal("Failed to write packet");
+ i += rc;
+ memcpy(buff+i, &target, sizeof(struct nodeid));
+ i += sizeof(struct nodeid);
+ rc = snprintf(buff+i, 128-i, "e1:q9:find_node1:t%d:%d1:y1:qe", (int)(log10(reqId+1)+1), reqId);
+ if(rc < 0)
+ fatal("Failed to write packet");
+ i += rc;
+
+ message->payload_len = i;
+ (*msgbuff->messages)++;
+
+ return 0;
+}
+
+void getclient_response(struct dht* dht, struct nodeid* self, char* packet, size_t packet_len, int socket, struct sockaddr* remote, socklen_t remote_len, struct msgbuff* msgbuff) {
+ struct benc_node stream[256];
+ struct bcursor bcursor;
+ bcur_open(&bcursor, packet, packet+packet_len, stream, 256);
+
+ if(bcursor.end - bcursor.readhead <= 0) {
+ err("Reponse too short");
+ exit(EXIT_FAILURE);
+ }
+
+ struct nodeid id;
+ uint8_t nodes_len;
+ struct nodeid nodes[8];
+ struct in_addr ips[8];
+ uint16_t ports[8];
+
+
+ // Read the payload
+ {
+ // Check that we have a dict
+ if(bcursor.readhead->type != BNT_DICT) {
+ err("Response is not a dict");
+ exit(EXIT_FAILURE);
+ }
+ bcur_next(&bcursor, 1);
+
+ bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING}, (const char*[]){"r"}, (const size_t[]){1}, 1);
+ // Skip the key
+ bcur_next(&bcursor, 1);
+
+ if(bcursor.readhead->type != BNT_DICT) {
+ err("Wrong value type for response");
+ exit(EXIT_FAILURE);
+ }
+
+ // Skip the dict element
+ bcur_next(&bcursor, 1);
+
+ uint8_t parts = 0;
+ while(bcursor.readhead->type != BNT_END) {
+ switch(bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING, BNT_STRING}, (const char*[]){"nodes", "id"}, (const size_t[]){5, 2}, 2)) {
+ case 0:
+ // Skip the key
+ bcur_next(&bcursor, 1);
+
+ if(bcursor.readhead->type != BNT_STRING) {
+ fatal("Nodes must be a string");
+ }
+
+ if((bcursor.readhead->size % 26) != 0) {
+ fatal("Nodes string value must be a multiple of 26");
+ }
+
+ nodes_len = MIN(bcursor.readhead->size/26, 8);
+ dbg("Remote gave us %d new candidates", nodes_len);
+ for(int i = 0; i < nodes_len; i++) {
+ memcpy(nodes+i, bcursor.readhead->loc+(26*i), 20);
+ memcpy(ips+i, bcursor.readhead->loc+(26*i)+20, 4);
+ memcpy(ports+i, bcursor.readhead->loc+(26*i)+24, 2);
+ }
+
+ parts++;
+
+ // Skip the value
+ bcur_next(&bcursor, 1);
+ break;
+ case 1:
+ // Skip the key
+ bcur_next(&bcursor, 1);
+
+ if(bcursor.readhead->type != BNT_STRING) {
+ err("Wrong value type for response");
+ exit(EXIT_FAILURE);
+ }
+
+ if(bcursor.readhead->size != 20) {
+ err("remote node id was not 20 bytes long");
+ exit(EXIT_FAILURE);
+ }
+
+ memcpy(&id, bcursor.readhead->loc, 20);
+
+ parts++;
+
+ // Skip the value
+ bcur_next(&bcursor, 1);
+ break;
+ }
+ }
+
+ if(parts < 2) {
+ fatal("Response didn't contain the expected values");
+ }
+ }
+
+ // Print the candidates
+ for(uint8_t i = 0; i < nodes_len; i++) {
+ dbgl_id(&nodes[i]);
+ printf("Candidate %s:%d\n", inet_ntoa(ips[i]), ntohs(ports[i]));
+
+ struct sockaddr_in dest = {
+ .sin_family = AF_INET,
+ .sin_addr = ips[i],
+ .sin_port = ports[i],
+ };
+
+ if(routing_interested(&nodes[i])) {
+ int rc = send_ping(dht, self, socket, (struct sockaddr*)&dest, sizeof(struct sockaddr_in), msgbuff);
+ if(rc != 0) {
+ err("send_ping failed %d", rc);
+ }
+ } else {
+ dbg("Not interested in node");
+ }
+ }
+
+ struct entry* entry;
+ routing_offer(&id, &entry);
+ struct sockaddr_in* ipv4 = (struct sockaddr_in*)remote;
+ entry->addr.ip = ipv4->sin_addr.s_addr;
+ entry->addr.port = ipv4->sin_port;
+ entry->last = time(NULL) + UNCERTAIN_TIME;
+}
+
+enum commandType {
+ CT_QUERY,
+ CT_RESPONSE,
+ CT_ERROR,
+};
+
+void proto_begin(struct dht* dht, struct message** output, const struct message* const output_end) {
+ routing_flush();
+ struct msgbuff msgbuff = {
+ output,
+ output_end,
+ };
+
+ for(int i = 0; i < MAX_DISC; i++) {
+ dht->addrs[i] = UNDEF_ADDR;
+ }
+
+ for(int i = 0; i < MAX_INFLIGHT; i++) {
+ dht->reqalloc[i] = false;
+ }
+
+ routing_init(&dht->self);
+ dbgl_id(&dht->self);
+
+ dht->sfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ if(dht->sfd == -1) {
+ err("Failed creating socket");
+ exit(1);
+ }
+ struct sockaddr_in bindAddr = {0};
+ bindAddr.sin_family = AF_INET;
+ bindAddr.sin_port = htons(6881);
+ bindAddr.sin_addr.s_addr = htonl(INADDR_ANY);
+ bind(dht->sfd, (struct sockaddr*)&bindAddr, sizeof(struct sockaddr_in));
+
+ struct addrinfo hints = {0};
+ hints.ai_family = AF_INET;
+ hints.ai_socktype = SOCK_DGRAM;
+ hints.ai_protocol = IPPROTO_UDP;
+ hints.ai_flags = AI_NUMERICSERV;
+
+ struct addrinfo* res;
+ int rc = getaddrinfo("router.bittorrent.com", "6881", &hints, &res);
+ if(rc != 0) {
+ err("Failed getting the bootstrap ip: %s", gai_strerror(rc));
+ exit(EXIT_FAILURE);
+ }
+
+ for(struct addrinfo* cur = res; cur != NULL; cur = cur->ai_next) {
+ char buff[128];
+ inet_ntop(cur->ai_family, &((struct sockaddr_in*)cur->ai_addr)->sin_addr, buff, 128);
+ dbg("IP %s", buff);
+
+ /* size_t i = 0; */
+ /* int rc = snprintf(buff+i, 128-i, "d1:ad2:id20:"); */
+ /* i += rc; */
+ /* memcpy(buff+i, &self, sizeof(struct nodeid)); */
+ /* i += sizeof(struct nodeid); */
+ /* rc = snprintf(buff+i, 128-i, "e1:q4:ping1:t2:ab1:y1:qe"); */
+ /* i += rc; */
+
+ send_ping(dht, &dht->self, dht->sfd, cur->ai_addr, cur->ai_addrlen, &msgbuff);
+ }
+
+ freeaddrinfo(res);
+}
+
+void proto_end(struct dht* dht) {
+ close(dht->sfd);
+}
+
+int proto_run(struct dht* dht, char* buff, size_t recv_len, struct sockaddr_in* remote, socklen_t remote_len, struct message** output, const struct message* const output_end) {
+ struct msgbuff msgbuff = {
+ output,
+ output_end,
+ };
+
+ if(recv_len == -1 && errno == ETIMEDOUT) {
+ time_t now = time(NULL);
+ struct entry* oldest = NULL;
+ routing_oldest(&oldest);
+ while(oldest != NULL) {
+ if(difftime(oldest->last, now) > 0.0)
+ break;
+ dbg("============ Ping uncertain node");
+
+ struct sockaddr_in dest = {0};
+ dest.sin_family = AF_INET;
+ dest.sin_addr.s_addr = oldest->addr.ip;
+ dest.sin_port = oldest->addr.port;
+ int rc = send_ping(dht, &dht->self, dht->sfd, (const struct sockaddr*)&dest, sizeof(dest), &msgbuff);
+ if(rc != 0) {
+ fatal("NOPE %d", rc);
+ }
+
+ oldest->last = now + 30;
+ routing_oldest(&oldest);
+ }
+
+ return 0;
+ }
+ printf("Received packet from %s:%d\n", inet_ntoa(remote->sin_addr), ntohs(remote->sin_port));
+
+ struct bcursor bcursor;
+ struct benc_node stream[256];
+ bcur_open(&bcursor, buff, buff+recv_len, stream, 256);
+ benc_print(bcursor.readhead, bcursor.end - bcursor.readhead);
+
+ if(bcursor.readhead->type != BNT_DICT) {
+ fatal("First value is not a dict");
+ }
+ bcur_next(&bcursor, 1);
+
+ bool discard = false;
+ enum commandType type;
+ bool transaction_set = false;
+ char transaction[64];
+ size_t transaction_len;
+ bool query_set = false;
+ char query[64];
+ size_t query_len;
+ while(bcursor.readhead->type != BNT_END) {
+ switch(bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING, BNT_STRING, BNT_STRING}, (const char*[]){"y", "t", "q"}, (const size_t[]){1, 1, 1}, 3)) {
+ case 0:
+ // Skip the key
+ bcur_next(&bcursor, 1);
+ if(*bcursor.readhead->loc == 'r') {
+ type = CT_RESPONSE;
+ } else if(*bcursor.readhead->loc == 'q') {
+ type = CT_QUERY;
+ } else if(*bcursor.readhead->loc == 'e') {
+ type = CT_ERROR;
+ } else {
+ fatal("Unknown command type %c", *bcursor.readhead->loc);
+ }
+ // Skip the value
+ bcur_next(&bcursor, 1);
+ break;
+ case 1: {
+ // Skip the key
+ bcur_next(&bcursor, 1);
+ if(bcursor.readhead->size > 64-1)
+ fatal("Transaction string too long");
+
+ transaction_set = true;
+ transaction_len = bcursor.readhead->size;
+ memcpy(transaction, bcursor.readhead->loc, transaction_len);
+ transaction[transaction_len] = '\0';
+
+ // Skip the value
+ bcur_next(&bcursor, 1);
+ break;
+ }
+ case 2: {
+ bcur_next(&bcursor, 1);
+ query_set = true;
+ query_len = bcursor.readhead->size;
+ memcpy(query, bcursor.readhead->loc, query_len);
+ query[query_len] = '\0';
+ bcur_next(&bcursor, 1);
+ }
+ }
+ }
+
+ if(discard){
+ return 0;
+ }
+
+ if(type == CT_RESPONSE) {
+ uint32_t transaction_number;
+
+ if(!transaction_set)
+ fatal("No transaction in response");
+
+ // Temporary null terminate the string to parse the number without a copy
+ char* end;
+ dbg("Transaction %s", transaction);
+ transaction_number = strtol(transaction, &end, 10);
+
+ if(end != transaction+transaction_len) {
+ err("DISCARD: Transaction id is not a number %.*s", (int)transaction_len, transaction);
+ return 0;
+ }
+
+ uint16_t reqId;
+ if(!find_req(dht, transaction_number, &reqId)) {
+ err("DISCARD: unknown transaction id %d", transaction_number);
+ return 0;
+ }
+ dbg("Transaction id matches request %d", reqId);
+
+ if(sockaddr_cmp((struct sockaddr*)&dht->requestdata[reqId].addr, (struct sockaddr*)remote) != 0) {
+ err("DISCARD: Unexpected IP for valid transaction");
+ return 0;
+ }
+
+ dht->requestdata[reqId].fun(dht, &dht->self, buff, recv_len, dht->sfd, (struct sockaddr*)remote, remote_len, &msgbuff);
+ dht->reqalloc[reqId] = false;
+ } else if(type == CT_QUERY) { // Must be a query
+ if(!query_set)
+ fatal("No query function in query request");
+ if(!transaction_set)
+ fatal("No transaction in request");
+
+ assert(strlen(query) == query_len);
+
+ assert(*msgbuff.messages < msgbuff.messages_end);
+ struct message* message = *msgbuff.messages;
+
+ char* end = message->payload+128;
+ char* cursor = message->payload;
+
+ int rc = snprintf(cursor, end-cursor , "d1:t%ld:", transaction_len);
+ if(rc < 0)
+ return EPERM;
+ cursor += rc;
+ memcpy(cursor, transaction, transaction_len);
+ cursor += transaction_len;
+ rc = snprintf(cursor, end-cursor, "1:y1:r1:r");
+ if(rc < 0)
+ return EPERM;
+ cursor += rc;
+
+ rc = handle_request(&dht->self, query, buff, recv_len, &cursor, end-cursor-1);
+ if(rc != 0) fatal("Error handling request");
+
+ rc = snprintf(cursor, end-cursor, "e");
+ if(rc < 0)
+ return EPERM;
+ cursor += rc;
+ assert(cursor < end);
+
+ message->payload_len = cursor - message->payload;
+
+ memcpy(&message->dest, remote, remote_len);
+ message->dest_len = remote_len;
+ (*msgbuff.messages)++;
+ }
+
+ return 0;
+}
diff --git a/src/proto.h b/src/proto.h
new file mode 100644
index 0000000..85dd310
--- /dev/null
+++ b/src/proto.h
@@ -0,0 +1,44 @@
+#pragma once
+
+#include "routing.h"
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+// 192.0.2.0
+#define UNDEF_ADDR (struct in_addr){0xC0000200}
+#define MAX_DISC 32
+#define MAX_INFLIGHT 32
+
+struct dht;
+struct msgbuff;
+typedef void (*cont)(struct dht* dht, struct nodeid* self, char* packet, size_t packet_len, int socket, struct sockaddr* remote, socklen_t remote_len, struct msgbuff* msgbuff);
+
+struct discovery {
+ uint16_t port;
+ struct nodeid expected_id;
+};
+
+struct dht {
+ struct nodeid self;
+ int sfd;
+
+ struct in_addr addrs[MAX_DISC];
+ struct discovery pending_discover[MAX_DISC];
+
+ bool reqalloc[MAX_INFLIGHT];
+ struct {
+ struct sockaddr_storage addr;
+ cont fun;
+ } requestdata[MAX_INFLIGHT];
+};
+
+struct message {
+ char payload[128];
+ size_t payload_len;
+ struct sockaddr_storage dest;
+ socklen_t dest_len;
+};
+
+void proto_begin(struct dht* dht, struct message** output, const struct message* const output_end);
+int proto_run(struct dht* dht, char* buffer, size_t buffer_len, struct sockaddr_in* remote, socklen_t remote_len, struct message** output, const struct message* const output_end);
+void proto_end(struct dht* dht);
diff --git a/src/routing.c b/src/routing.c
index b8ab037..64d5353 100644
--- a/src/routing.c
+++ b/src/routing.c
@@ -1,5 +1,7 @@
#include "routing.h"
+#include "log.h"
+
#include <assert.h>
#include <limits.h>
#include <string.h>
@@ -41,6 +43,7 @@ struct entry table[ROUTINGSIZE];
void routing_init(struct nodeid* myid) {
myID = *myid;
+ routing_flush();
}
void routing_flush() {
@@ -48,7 +51,7 @@ void routing_flush() {
}
// Calculate the common bit prefix between two node ids.
-uint8_t prefix(struct nodeid* a, struct nodeid* b) {
+static uint8_t prefix(struct nodeid* a, struct nodeid* b) {
uint8_t c = 0;
for(uint8_t i = 0; i < 5; i++) {
uint32_t word = a->inner[i] ^ b->inner[i];
@@ -64,13 +67,13 @@ uint8_t prefix(struct nodeid* a, struct nodeid* b) {
return c;
}
-int8_t scan(uint16_t baseIndex, struct nodeid* id) {
+static int8_t scan(uint16_t baseIndex, struct nodeid* id) {
assert(baseIndex < ROUTINGSIZE - BUCKETSIZE);
- int8_t index = -1;
+ int8_t index = -2;
for(size_t i = baseIndex; i < baseIndex + BUCKETSIZE; i++) {
if(!table[i].set) {
- index = index == -1 ? i - baseIndex : index;
+ index = index == -2 ? i - baseIndex : index;
continue;
}
@@ -82,6 +85,28 @@ int8_t scan(uint16_t baseIndex, struct nodeid* id) {
return index;
}
+static uint16_t base_bucket(struct nodeid* id) {
+ uint16_t bucketIndex = prefix(&myID, id);
+ assert(bucketIndex != IDBITS);
+
+ // If they are sufficiently similar they end up in the final bucket. Clamp the index to ensure.
+ bucketIndex = bucketIndex > (IDBITS - BUCKETBITS) ? (IDBITS - BUCKETBITS) : bucketIndex;
+ assert(bucketIndex <= IDBITS - BUCKETBITS);
+
+ return bucketIndex * BUCKETSIZE;
+}
+
+struct entry* routing_get(struct nodeid* id) {
+ uint16_t baseIndex = base_bucket(id);
+ for(size_t i = baseIndex; i < baseIndex + BUCKETSIZE; i++) {
+ if(memcmp(&table[i].id, id, sizeof(struct nodeid)) == 0) {
+ return &table[i];
+ }
+ }
+
+ return NULL;
+}
+
bool routing_interested(struct nodeid* id) {
uint16_t bucketIndex = prefix(&myID, id);
// The nodeid is the same as our own
@@ -89,14 +114,10 @@ bool routing_interested(struct nodeid* id) {
return false;
}
- // If they are sufficiently similar they end up in the final bucket. Clamp the index to ensure.
- bucketIndex = bucketIndex > (IDBITS - BUCKETBITS) ? (IDBITS - BUCKETBITS) : bucketIndex;
- assert(bucketIndex <= IDBITS - BUCKETBITS);
-
- uint16_t baseIndex = bucketIndex * BUCKETSIZE;
+ uint16_t baseIndex = base_bucket(id);
int8_t inBucketIndex = scan(baseIndex, id);
- if(inBucketIndex == -1) {
+ if(inBucketIndex < 0) {
// The bucket either already contains the node, or it has no more space
return false;
}
@@ -112,11 +133,7 @@ bool routing_offer(struct nodeid* id, struct entry **dest) {
return false;
}
- // If they are sufficiently similar they end up in the final bucket. Clamp the index to ensure.
- bucketIndex = bucketIndex > (IDBITS - BUCKETBITS) ? (IDBITS - BUCKETBITS) : bucketIndex;
- assert(bucketIndex <= IDBITS - BUCKETBITS);
-
- uint16_t baseIndex = bucketIndex * BUCKETSIZE;
+ uint16_t baseIndex = base_bucket(id);
int8_t inBucketIndex = scan(baseIndex, id);
if(inBucketIndex == -1) {
@@ -181,3 +198,20 @@ size_t routing_closest(struct nodeid* needle, size_t n, struct entry** res) {
return read;
}
+void routing_oldest(struct entry** dest) {
+ *dest = NULL;
+
+ for(struct entry* entry = table; entry < table+ROUTINGSIZE; entry++){
+ if(!entry->set)
+ continue;
+
+ if(*dest == NULL) {
+ *dest = entry;
+ continue;
+ }
+
+ if(difftime((*dest)->last, entry->last) > 0.0) {
+ *dest = entry;
+ }
+ }
+}
diff --git a/src/routing.h b/src/routing.h
index 5c98f13..7f1d19e 100644
--- a/src/routing.h
+++ b/src/routing.h
@@ -29,4 +29,7 @@ void routing_init(struct nodeid* myid);
void routing_flush();
bool routing_interested(struct nodeid* id);
bool routing_offer(struct nodeid* id, struct entry **dest);
+void routing_oldest(struct entry** dest);
size_t routing_closest(struct nodeid* needle, size_t n, struct entry** res);
+
+struct entry* routing_get(struct nodeid* id);
generated by cgit v1.2.3 (git 2.25.1) at 2026-08-03 22:02:10 +0000