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authorMatthias Schiffer <mschiffer@universe-factory.net>2014-05-28 04:52:58 +0200
committerMatthias Schiffer <mschiffer@universe-factory.net>2014-05-28 04:52:58 +0200
commitd5da100c55d80391d2e941a41c0e0dccf2a6e33e (patch)
tree1aca67556ed8ea1e2f9fa2a73ebf1a84e8cd34a7 /src/handshake.c
parentd859894f7a88e07e7beae8dc355278cfd6c185e2 (diff)
downloadfastd-d5da100c55d80391d2e941a41c0e0dccf2a6e33e.tar
fastd-d5da100c55d80391d2e941a41c0e0dccf2a6e33e.zip
Still more documentation
Diffstat (limited to 'src/handshake.c')
-rw-r--r--src/handshake.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/src/handshake.c b/src/handshake.c
index d0d6016..e8b2197 100644
--- a/src/handshake.c
+++ b/src/handshake.c
@@ -23,6 +23,12 @@
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+/**
+ \file
+
+ Functions and structures for composing and decomposing handshake packets
+*/
+
#include "handshake.h"
#include "method.h"
@@ -30,6 +36,7 @@
#include <fastd_version.h>
+/** Human-readable names for the TLV record types */
static const char *const RECORD_TYPES[RECORD_MAX] = {
"handshake type",
"reply code",
@@ -50,10 +57,14 @@ static const char *const RECORD_TYPES[RECORD_MAX] = {
};
+/** Reads a TLV record as an 8bit integer */
#define AS_UINT8(ptr) (*(uint8_t*)(ptr).data)
+
+/** Reads a TLV record as a 16bit integer (big endian) */
#define AS_UINT16(ptr) ((*(uint8_t*)(ptr).data) + (*((uint8_t*)(ptr).data+1) << 8))
+/** Generates a zero-separated list of supported methods */
static uint8_t* create_method_list(size_t *len) {
*len = 0;
@@ -72,6 +83,7 @@ static uint8_t* create_method_list(size_t *len) {
return ret;
}
+/** Checks if a string is equal to a buffer with a maximum length */
static inline bool string_equal(const char *str, const char *buf, size_t maxlen) {
if (strlen(str) != strnlen(buf, maxlen))
return false;
@@ -79,10 +91,12 @@ static inline bool string_equal(const char *str, const char *buf, size_t maxlen)
return !strncmp(str, buf, maxlen);
}
+/** Checks if a string is equal to the value of a TLV record */
static inline bool record_equal(const char *str, const fastd_handshake_record_t *record) {
return string_equal(str, (const char*)record->data, record->length);
}
+/** Parses a list of zero-separated strings */
static fastd_string_stack_t* parse_string_list(const uint8_t *data, size_t len) {
const uint8_t *end = data+len;
fastd_string_stack_t *ret = NULL;
@@ -97,6 +111,7 @@ static fastd_string_stack_t* parse_string_list(const uint8_t *data, size_t len)
return ret;
}
+/** Allocates and initializes a new handshake packet */
static fastd_buffer_t new_handshake(uint8_t type, const fastd_method_info_t *method, bool with_method_list, size_t tail_space) {
size_t version_len = strlen(FASTD_VERSION);
size_t protocol_len = strlen(conf.protocol->name);
@@ -139,16 +154,19 @@ static fastd_buffer_t new_handshake(uint8_t type, const fastd_method_info_t *met
return buffer;
}
+/** Allocates and initializes a new initial handshake packet */
fastd_buffer_t fastd_handshake_new_init(size_t tail_space) {
return new_handshake(1, NULL, !conf.secure_handshakes, tail_space);
}
+/** Allocates and initializes a new reply handshake packet */
fastd_buffer_t fastd_handshake_new_reply(uint8_t type, const fastd_method_info_t *method, bool with_method_list, size_t tail_space) {
fastd_buffer_t buffer = new_handshake(type, method, with_method_list, tail_space);
fastd_handshake_add_uint8(&buffer, RECORD_REPLY_CODE, 0);
return buffer;
}
+/** Prints the error corresponding to the given reply code and error detail */
static void print_error(const char *prefix, const fastd_peer_address_t *remote_addr, uint8_t reply_code, uint8_t error_detail) {
const char *error_field_str;
@@ -174,6 +192,7 @@ static void print_error(const char *prefix, const fastd_peer_address_t *remote_a
}
}
+/** Sends an error reply to a peer */
static void send_error(fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, const fastd_handshake_t *handshake, uint8_t reply_code, uint8_t error_detail) {
print_error("sending", remote_addr, reply_code, error_detail);
@@ -190,6 +209,7 @@ static void send_error(fastd_socket_t *sock, const fastd_peer_address_t *local_a
fastd_send_handshake(sock, local_addr, remote_addr, peer, buffer);
}
+/** Parses the TLV records of a handshake */
static inline fastd_handshake_t parse_tlvs(const fastd_buffer_t *buffer) {
fastd_handshake_t handshake = {};
@@ -232,6 +252,7 @@ static inline fastd_handshake_t parse_tlvs(const fastd_buffer_t *buffer) {
return handshake;
}
+/** Prints the error found in a received handshake */
static inline void print_error_reply(const fastd_peer_address_t *remote_addr, const fastd_handshake_t *handshake) {
uint8_t reply_code = AS_UINT8(handshake->records[RECORD_REPLY_CODE]);
uint8_t error_detail = RECORD_MAX;
@@ -242,6 +263,7 @@ static inline void print_error_reply(const fastd_peer_address_t *remote_addr, co
print_error("received", remote_addr, reply_code, error_detail);
}
+/** Does some basic validity checks on a received handshake */
static inline bool check_records(fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, const fastd_handshake_t *handshake) {
if (handshake->records[RECORD_PROTOCOL_NAME].data) {
if (!record_equal(conf.protocol->name, &handshake->records[RECORD_PROTOCOL_NAME])) {
@@ -281,6 +303,7 @@ static inline bool check_records(fastd_socket_t *sock, const fastd_peer_address_
return true;
}
+/** Returns the method info with a specified name and length */
static inline const fastd_method_info_t* get_method_by_name(const char *name, size_t n) {
char name0[n+1];
memcpy(name0, name, n);
@@ -289,6 +312,7 @@ static inline const fastd_method_info_t* get_method_by_name(const char *name, si
return fastd_method_get_by_name(name0);
}
+/** Returns the most appropriate method to negotiate with a peer a handshake was received from */
static inline const fastd_method_info_t* get_method(const fastd_handshake_t *handshake) {
if (handshake->records[RECORD_METHOD_LIST].data && handshake->records[RECORD_METHOD_LIST].length) {
fastd_string_stack_t *method_list = parse_string_list(handshake->records[RECORD_METHOD_LIST].data, handshake->records[RECORD_METHOD_LIST].length);
@@ -314,6 +338,7 @@ static inline const fastd_method_info_t* get_method(const fastd_handshake_t *han
return get_method_by_name((const char*)handshake->records[RECORD_METHOD_NAME].data, handshake->records[RECORD_METHOD_NAME].length);
}
+/** Handles a handshake packet */
void fastd_handshake_handle(fastd_socket_t *sock, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *remote_addr, fastd_peer_t *peer, fastd_buffer_t buffer) {
char *peer_version = NULL;
const fastd_method_info_t *method = NULL;