diff options
Diffstat (limited to 'src/handshake.c')
| -rw-r--r-- | src/handshake.c | 25 |
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; |