Document *everything*

7 files changed, 204 insertions, 35 deletions

diff --git a/src/methods/cipher_test/cipher_test.c b/src/methods/cipher_test/cipher_test.c
index 52bca0f..7e064ba 100644
--- a/src/methods/cipher_test/cipher_test.c
+++ b/src/methods/cipher_test/cipher_test.c
@@ -23,25 +23,37 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   cipher-test method provider (testing and benchmarking only)
+
+   The cipher-test method provider performs encryption only and can be used to test
+   and benchmark cipher implementations.
+*/
+
 
 #include "../../crypto.h"
 #include "../../method.h"
 #include "../common.h"
 
 
+/** A specific method provided by this provider */
 struct fastd_method {
-	const fastd_cipher_info_t *cipher_info;
+	const fastd_cipher_info_t *cipher_info;		/**< The cipher used */
 };
 
+/** The method-specific session state */
 struct fastd_method_session_state {
-	fastd_method_common_t common;
+	fastd_method_common_t common;			/**< The common method state */
 
-	const fastd_method_t *method;
-	const fastd_cipher_t *cipher;
-	fastd_cipher_state_t *cipher_state;
+	const fastd_method_t *method;			/**< The specific method used */
+	const fastd_cipher_t *cipher;			/**< The cipher implementation used */
+	fastd_cipher_state_t *cipher_state;		/**< The cipher state */
 };
 
 
+/** Instanciates a method using a name of the pattern "<cipher>+cipher-test" */
 static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	fastd_method_t m;
 
@@ -66,14 +78,17 @@ static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	return true;
 }
 
+/** Frees a method */
 static void method_destroy(fastd_method_t *method) {
 	free(method);
 }
 
+/** Returns the key length used by a method */
 static size_t method_key_length(const fastd_method_t *method) {
 	return method->cipher_info->key_length;
 }
 
+/** Initializes a session */
 static fastd_method_session_state_t* method_session_init(const fastd_method_t *method, const uint8_t *secret, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
@@ -87,22 +102,27 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
 	return session;
 }
 
+/** Checks if the session is currently valid */
 static bool method_session_is_valid(fastd_method_session_state_t *session) {
 	return (session && fastd_method_session_common_is_valid(&session->common));
 }
 
+/** Checks if this side is the initator of the session */
 static bool method_session_is_initiator(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_is_initiator(&session->common);
 }
 
+/** Checks if the session should be refreshed */
 static bool method_session_want_refresh(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_want_refresh(&session->common);
 }
 
+/** Marks the session as superseded */
 static void method_session_superseded(fastd_method_session_state_t *session) {
 	fastd_method_session_common_superseded(&session->common);
 }
 
+/** Frees the session state */
 static void method_session_free(fastd_method_session_state_t *session) {
 	if (session) {
 		session->cipher->free(session->cipher_state);
@@ -110,6 +130,8 @@ static void method_session_free(fastd_method_session_state_t *session) {
 	}
 }
 
+
+/** Encrypts a packet and adds the common method header */
 static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len;
 	*out = fastd_buffer_alloc(in.len, alignto(COMMON_HEADBYTES, 16), sizeof(fastd_block128_t)+tail_len);
@@ -140,6 +162,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state
 	return true;
 }
 
+/** Decrypts a packet */
 static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	if (in.len < COMMON_HEADBYTES)
 		return false;
@@ -184,6 +207,8 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses
 	return true;
 }
 
+
+/** The cipher-test method provider */
 const fastd_method_provider_t fastd_method_cipher_test = {
 	.max_overhead = COMMON_HEADBYTES,
 	.min_encrypt_head_space = 0,
diff --git a/src/methods/composed_gmac/composed_gmac.c b/src/methods/composed_gmac/composed_gmac.c
index 887fb5c..6636e49 100644
--- a/src/methods/composed_gmac/composed_gmac.c
+++ b/src/methods/composed_gmac/composed_gmac.c
@@ -23,37 +23,51 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   composed-gmac method provider
+
+   composed-gmac combines any cipher (or null) with GMAC, while another cipher is
+   used to generate the GHASH keys. Combining the null cipher with GMAC allows creating
+   unencrypted, authenticated-only methods.
+*/
+
 
 #include "../../crypto.h"
 #include "../../method.h"
 #include "../common.h"
 
 
+/** A block of zeros */
 static const fastd_block128_t ZERO_BLOCK = {};
 
 
+/** A specific method provided by this provider */
 struct fastd_method {
-	const fastd_cipher_info_t *cipher_info;
-	const fastd_cipher_info_t *gmac_cipher_info;
-	const fastd_mac_info_t *ghash_info;
+	const fastd_cipher_info_t *cipher_info;		/**< The cipher used for encryption */
+	const fastd_cipher_info_t *gmac_cipher_info;	/**< The cipher used for authenticaton */
+	const fastd_mac_info_t *ghash_info;		/**< GHASH */
 };
 
+/** The method-specific session state */
 struct fastd_method_session_state {
-	fastd_method_common_t common;
+	fastd_method_common_t common;			/**< The common method state */
 
-	const fastd_method_t *method;
+	const fastd_method_t *method;			/**< The specific method used */
 
-	const fastd_cipher_t *cipher;
-	fastd_cipher_state_t *cipher_state;
+	const fastd_cipher_t *cipher;			/**< The cipher implementation used for encryption */
+	fastd_cipher_state_t *cipher_state;		/**< The cipher state for encryption */
 
-	const fastd_cipher_t *gmac_cipher;
-	fastd_cipher_state_t *gmac_cipher_state;
+	const fastd_cipher_t *gmac_cipher;		/**< The cipher implementation used for authentication */
+	fastd_cipher_state_t *gmac_cipher_state;	/**< The cipher state for authentication */
 
-	const fastd_mac_t *ghash;
-	fastd_mac_state_t *ghash_state;
+	const fastd_mac_t *ghash;			/**< The GHASH implementation */
+	fastd_mac_state_t *ghash_state;			/**< The GHASH state */
 };
 
 
+/** Instanciates a method using a name of the pattern "<cipher>+<cipher>+gmac" (or "<cipher>+<cipher>-gmac" for block ciphers in counter mode, e.g. null+aes128-gmac instead of null+aes128-ctr+gmac) */
 static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	fastd_method_t m;
 
@@ -107,15 +121,17 @@ static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	return true;
 }
 
+/** Frees a method */
 static void method_destroy(fastd_method_t *method) {
 	free(method);
 }
 
-
+/** Returns the key length used by a method */
 static size_t method_key_length(const fastd_method_t *method) {
 	return method->cipher_info->key_length + method->gmac_cipher_info->key_length;
 }
 
+/** Initializes a session */
 static fastd_method_session_state_t* method_session_init(const fastd_method_t *method, const uint8_t *secret, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
@@ -148,22 +164,27 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
 	return session;
 }
 
+/** Checks if the session is currently valid */
 static bool method_session_is_valid(fastd_method_session_state_t *session) {
 	return (session && fastd_method_session_common_is_valid(&session->common));
 }
 
+/** Checks if this side is the initator of the session */
 static bool method_session_is_initiator(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_is_initiator(&session->common);
 }
 
+/** Checks if the session should be refreshed */
 static bool method_session_want_refresh(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_want_refresh(&session->common);
 }
 
+/** Marks the session as superseded */
 static void method_session_superseded(fastd_method_session_state_t *session) {
 	fastd_method_session_common_superseded(&session->common);
 }
 
+/** Frees the session state */
 static void method_session_free(fastd_method_session_state_t *session) {
 	if (session) {
 		session->cipher->free(session->cipher_state);
@@ -174,6 +195,7 @@ static void method_session_free(fastd_method_session_state_t *session) {
 	}
 }
 
+/** Writes the size of the input in bits to a block (in a way different from the generic-gmac methods) */
 static inline void put_size(fastd_block128_t *out, size_t len) {
 	memset(out, 0, sizeof(fastd_block128_t));
 	out->b[3] = len >> 29;
@@ -183,6 +205,7 @@ static inline void put_size(fastd_block128_t *out, size_t len) {
 	out->b[7] = len << 3;
 }
 
+/** Encrypts and authenticates a packet */
 static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	size_t tail_len = alignto(in.len, sizeof(fastd_block128_t))-in.len;
 	*out = fastd_buffer_alloc(sizeof(fastd_block128_t)+in.len, alignto(COMMON_HEADBYTES, 16), sizeof(fastd_block128_t)+tail_len);
@@ -232,6 +255,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state
 	return true;
 }
 
+/** Verifies and decrypts a packet */
 static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	if (in.len < COMMON_HEADBYTES+sizeof(fastd_block128_t))
 		return false;
@@ -294,6 +318,8 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses
 	return true;
 }
 
+
+/** The composed-gmac method provider */
 const fastd_method_provider_t fastd_method_composed_gmac = {
 	.max_overhead = COMMON_HEADBYTES + sizeof(fastd_block128_t),
 	.min_encrypt_head_space = 0,
diff --git a/src/methods/generic_gmac/generic_gmac.c b/src/methods/generic_gmac/generic_gmac.c
index 6b84a95..546cd50 100644
--- a/src/methods/generic_gmac/generic_gmac.c
+++ b/src/methods/generic_gmac/generic_gmac.c
@@ -23,30 +23,41 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   generic-gmac method provider
+
+   generic-gmac can combine any stream cipher with the GMAC authentication.
+*/
+
 
 #include "../../crypto.h"
 #include "../../method.h"
 #include "../common.h"
 
 
+/** A specific method provided by this provider */
 struct fastd_method {
-	const fastd_cipher_info_t *cipher_info;
-	const fastd_mac_info_t *ghash_info;
+	const fastd_cipher_info_t *cipher_info;		/**< The cipher used */
+	const fastd_mac_info_t *ghash_info;		/**< GHASH */
 };
 
+/** The method-specific session state */
 struct fastd_method_session_state {
-	fastd_method_common_t common;
+	fastd_method_common_t common;			/**< The common method state */
 
-	const fastd_method_t *method;
+	const fastd_method_t *method;			/**< The specific method used */
 
-	const fastd_cipher_t *cipher;
-	fastd_cipher_state_t *cipher_state;
+	const fastd_cipher_t *cipher;			/**< The cipher implementation used */
+	fastd_cipher_state_t *cipher_state;		/**< The cipher state */
 
-	const fastd_mac_t *ghash;
-	fastd_mac_state_t *ghash_state;
+	const fastd_mac_t *ghash;			/**< The GHASH implementation */
+	fastd_mac_state_t *ghash_state;			/**< The GHASH state */
 };
 
 
+/** Instanciates a method using a name of the pattern "<cipher>+gmac" (or "<cipher>-gcm" for block ciphers in counter mode, e.g. aes128-gcm instead of aes128-ctr+gmac) */
 static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	fastd_method_t m;
 
@@ -85,14 +96,17 @@ static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	return true;
 }
 
+/** Frees a method */
 static void method_destroy(fastd_method_t *method) {
 	free(method);
 }
 
+/** Returns the key length used by a method */
 static size_t method_key_length(const fastd_method_t *method) {
 	return method->cipher_info->key_length;
 }
 
+/** Initializes a session */
 static fastd_method_session_state_t* method_session_init(const fastd_method_t *method, const uint8_t *secret, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
@@ -121,22 +135,27 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
 	return session;
 }
 
+/** Checks if the session is currently valid */
 static bool method_session_is_valid(fastd_method_session_state_t *session) {
 	return (session && fastd_method_session_common_is_valid(&session->common));
 }
 
+/** Checks if this side is the initator of the session */
 static bool method_session_is_initiator(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_is_initiator(&session->common);
 }
 
+/** Checks if the session should be refreshed */
 static bool method_session_want_refresh(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_want_refresh(&session->common);
 }
 
+/** Marks the session as superseded */
 static void method_session_superseded(fastd_method_session_state_t *session) {
 	fastd_method_session_common_superseded(&session->common);
 }
 
+/** Frees the session state */
 static void method_session_free(fastd_method_session_state_t *session) {
 	if (session) {
 		session->cipher->free(session->cipher_state);
@@ -146,6 +165,7 @@ static void method_session_free(fastd_method_session_state_t *session) {
 	}
 }
 
+/** Writes the size of the input in bits to a block */
 static inline void put_size(fastd_block128_t *out, size_t len) {
 	memset(out, 0, sizeof(fastd_block128_t));
 	out->b[11] = len >> 29;
@@ -155,6 +175,8 @@ static inline void put_size(fastd_block128_t *out, size_t len) {
 	out->b[15] = len << 3;
 }
 
+
+/** Encrypts and authenticates a packet */
 static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	fastd_buffer_pull_head_zero(&in, sizeof(fastd_block128_t));
 
@@ -199,6 +221,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state
 	return true;
 }
 
+/** Verifies and decrypts a packet */
 static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	if (in.len < COMMON_HEADBYTES+sizeof(fastd_block128_t))
 		return false;
@@ -255,6 +278,8 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses
 	return true;
 }
 
+
+/** The generic-gmac method provider */
 const fastd_method_provider_t fastd_method_generic_gmac = {
 	.max_overhead = COMMON_HEADBYTES + sizeof(fastd_block128_t),
 	.min_encrypt_head_space = sizeof(fastd_block128_t),
diff --git a/src/methods/generic_poly1305/generic_poly1305.c b/src/methods/generic_poly1305/generic_poly1305.c
index 0e2641c..142b50e 100644
--- a/src/methods/generic_poly1305/generic_poly1305.c
+++ b/src/methods/generic_poly1305/generic_poly1305.c
@@ -23,6 +23,15 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   generic-poly1305 method provider
+
+   The Poly1305 authenticator is very secure, but for performance reasons
+   not really recommendable on embedded systems.
+*/
+
 
 #include "../../crypto.h"
 #include "../../method.h"
@@ -31,23 +40,29 @@
 #include <crypto_onetimeauth_poly1305.h>
 
 
+/** The length of the key used by Poly1305 */
 #define KEYBYTES crypto_onetimeauth_poly1305_KEYBYTES
+
+/** The length of the authentication tag */
 #define TAGBYTES crypto_onetimeauth_poly1305_BYTES
 
 
+/** A specific method provided by this provider */
 struct fastd_method {
-	const fastd_cipher_info_t *cipher_info;
+	const fastd_cipher_info_t *cipher_info;		/**< The cipher used */
 };
 
+/** The method-specific session state */
 struct fastd_method_session_state {
-	fastd_method_common_t common;
+	fastd_method_common_t common;			/**< The common method state */
 
-	const fastd_method_t *method;
-	const fastd_cipher_t *cipher;
-	fastd_cipher_state_t *cipher_state;
+	const fastd_method_t *method;			/**< The specific method used */
+	const fastd_cipher_t *cipher;			/**< The cipher implementation used */
+	fastd_cipher_state_t *cipher_state;		/**< The cipher state */
 };
 
 
+/** Instanciates a method using a name of the pattern "<cipher>+poly1305" */
 static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	fastd_method_t m;
 
@@ -75,14 +90,17 @@ static bool method_create_by_name(const char *name, fastd_method_t **method) {
 	return true;
 }
 
+/** Frees a method */
 static void method_destroy(fastd_method_t *method) {
 	free(method);
 }
 
+/** Returns the key length used by a method */
 static size_t method_key_length(const fastd_method_t *method) {
 	return method->cipher_info->key_length;
 }
 
+/** Initializes a session */
 static fastd_method_session_state_t* method_session_init(const fastd_method_t *method, const uint8_t *secret, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
@@ -94,22 +112,27 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
 	return session;
 }
 
+/** Checks if the session is currently valid */
 static bool method_session_is_valid(fastd_method_session_state_t *session) {
 	return (session && fastd_method_session_common_is_valid(&session->common));
 }
 
+/** Checks if this side is the initator of the session */
 static bool method_session_is_initiator(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_is_initiator(&session->common);
 }
 
+/** Checks if the session should be refreshed */
 static bool method_session_want_refresh(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_want_refresh(&session->common);
 }
 
+/** Marks the session as superseded */
 static void method_session_superseded(fastd_method_session_state_t *session) {
 	fastd_method_session_common_superseded(&session->common);
 }
 
+/** Frees the session state */
 static void method_session_free(fastd_method_session_state_t *session) {
 	if (session) {
 		session->cipher->free(session->cipher_state);
@@ -117,6 +140,8 @@ static void method_session_free(fastd_method_session_state_t *session) {
 	}
 }
 
+
+/** Encrypts and authenticates a packet */
 static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	fastd_buffer_pull_head_zero(&in, KEYBYTES);
 
@@ -155,6 +180,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state
 	return true;
 }
 
+/** Verifies and decrypts a packet */
 static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	if (in.len < COMMON_HEADBYTES+TAGBYTES)
 		return false;
@@ -217,6 +243,8 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses
 	return true;
 }
 
+
+/** The generic-poly1305 method provider */
 const fastd_method_provider_t fastd_method_generic_poly1305 = {
 	.max_overhead = COMMON_HEADBYTES + TAGBYTES,
 	.min_encrypt_head_space = KEYBYTES,
diff --git a/src/methods/methods.c.in b/src/methods/methods.c.in
index 914d929..672ef70 100644
--- a/src/methods/methods.c.in
+++ b/src/methods/methods.c.in
@@ -23,16 +23,24 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   Generated list of supported method providers
+*/
+
 
 #include <src/method.h>
 
 
 @METHOD_DEFINITIONS@
 
+/** The list of method providers */
 static const fastd_method_provider_t *const providers[] = { @METHOD_LIST@
 };
 
 
+/** Searches for a provider providing a method and instanciates it */
 bool fastd_method_create_by_name(const char *name, const fastd_method_provider_t **provider, fastd_method_t **method) {
 	size_t i;
 	for (i = 0; i < array_size(providers); i++) {
diff --git a/src/methods/null/null.c b/src/methods/null/null.c
index 76fd961..3062fcf 100644
--- a/src/methods/null/null.c
+++ b/src/methods/null/null.c
@@ -23,27 +23,37 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   The null method not providing any encryption or authenticaton
+*/
 
 #include "../../method.h"
 
 
+/** The session state */
 struct fastd_method_session_state {
-	bool valid;
-	bool initiator;
+	bool valid;			/**< true if the session has not been invalidated */
+	bool initiator;			/**< true if this side is the initiator of the session */
 };
 
 
+/** Returns true if the name is "null" */
 static bool method_create_by_name(const char *name, fastd_method_t **method UNUSED) {
 	return !strcmp(name, "null");
 }
 
+/** Does nothing as the null provider provides only a single method */
 static void method_destroy(fastd_method_t *method UNUSED) {
 }
 
+/** Returns 0 */
 static size_t method_key_length(const fastd_method_t *method UNUSED) {
 	return 0;
 }
 
+/** Initiates a new null session */
 static fastd_method_session_state_t* method_session_init(const fastd_method_t *method UNUSED, const uint8_t *secret UNUSED, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
@@ -53,35 +63,49 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
 	return session;
 }
 
+/** Initiates a new null session (pre-v11 compat handshake) */
 static fastd_method_session_state_t* method_session_init_compat(const fastd_method_t *method, const uint8_t *secret, size_t length UNUSED, bool initiator) {
 	return method_session_init(method, secret, initiator);
 }
 
+/** Checks if the session is valid */
 static bool method_session_is_valid(fastd_method_session_state_t *session) {
 	return (session && session->valid);
 }
 
+/** Checks if this side is the initiator of the session */
 static bool method_session_is_initiator(fastd_method_session_state_t *session) {
 	return (session->initiator);
 }
 
+/** Returns false */
 static bool method_session_want_refresh(fastd_method_session_state_t *session UNUSED) {
 	return false;
 }
 
+/**
+   Marks the session as invalid
+
+   The session in invalidated without any delay to prevent packets of the new session being
+   mistaken to be valid for the old session
+*/
 static void method_session_superseded(fastd_method_session_state_t *session) {
 	session->valid = false;
 }
 
+/** Frees the session state */
 static void method_session_free(fastd_method_session_state_t *session) {
 	free(session);
 }
 
+/** Just returns the input buffer as the output */
 static bool method_passthrough(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session UNUSED, fastd_buffer_t *out, fastd_buffer_t in) {
 	*out = in;
 	return true;
 }
 
+
+/** The null method provider */
 const fastd_method_provider_t fastd_method_null = {
 	.max_overhead = 0,
 	.min_encrypt_head_space = 0,
diff --git a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
index f06e0f8..9f2d61c 100644
--- a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
+++ b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
@@ -23,6 +23,16 @@
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+/**
+   \file
+
+   The xsalsa20-poly1305 method provider (deprecated)
+
+   This provider is included for compatiblity reasons as pre-v11
+   xsalsa20-poly1305 was the recommended method. In new setups salsa20+poly1305
+   provided by the generic-poly1305 provider should be used as a replacement.
+*/
+
 
 #include "../../crypto.h"
 #include "../../method.h"
@@ -31,24 +41,29 @@
 #include <crypto_secretbox_xsalsa20poly1305.h>
 
 
+/** The session state */
 struct fastd_method_session_state {
-	fastd_method_common_t common;
+	fastd_method_common_t common;		/**< The common method state */
 
-	uint8_t key[crypto_secretbox_xsalsa20poly1305_KEYBYTES] __attribute__((aligned(8)));
+	uint8_t key[crypto_secretbox_xsalsa20poly1305_KEYBYTES] __attribute__((aligned(8))); /**< The encryption key */
 };
 
 
+/** Matches the method name "xsalsa20-poly1305" */
 static bool method_create_by_name(const char *name, fastd_method_t **method UNUSED) {
 	return !strcmp(name, "xsalsa20-poly1305");
 }
 
+/** Does nothing as this provider has only a single method */
 static void method_destroy(fastd_method_t *method UNUSED) {
 }
 
+/** Returns the key length used by xsalsa20-poly1305 */
 static size_t method_key_length(const fastd_method_t *method UNUSED) {
 	return crypto_secretbox_xsalsa20poly1305_KEYBYTES;
 }
 
+/** Initializes the session state */
 static fastd_method_session_state_t* method_session_init(const fastd_method_t *method UNUSED, const uint8_t *secret, bool initiator) {
 	fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
 
@@ -59,6 +74,7 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
 	return session;
 }
 
+/** Initializes the session state (pre-v11 compat handshake) */
 static fastd_method_session_state_t* method_session_init_compat(const fastd_method_t *method, const uint8_t *secret, size_t length, bool initiator) {
 	if (length < crypto_secretbox_xsalsa20poly1305_KEYBYTES)
 		exit_bug("xsalsa20-poly1305: tried to init with short secret");
@@ -66,22 +82,27 @@ static fastd_method_session_state_t* method_session_init_compat(const fastd_meth
 	return method_session_init(method, secret, initiator);
 }
 
+/** Checks if a session is currently valid */
 static bool method_session_is_valid(fastd_method_session_state_t *session) {
 	return (session && fastd_method_session_common_is_valid(&session->common));
 }
 
+/** Checks if this side is the initiator of the session */
 static bool method_session_is_initiator(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_is_initiator(&session->common);
 }
 
+/** Checks if the session should be refreshed */
 static bool method_session_want_refresh(fastd_method_session_state_t *session) {
 	return fastd_method_session_common_want_refresh(&session->common);
 }
 
+/** Marks the session as superseded */
 static void method_session_superseded(fastd_method_session_state_t *session) {
 	fastd_method_session_common_superseded(&session->common);
 }
 
+/** Frees the session state */
 static void method_session_free(fastd_method_session_state_t *session) {
 	if(session) {
 		secure_memzero(session, sizeof(fastd_method_session_state_t));
@@ -90,12 +111,19 @@ static void method_session_free(fastd_method_session_state_t *session) {
 }
 
 
+/**
+   Copies a nonce of length COMMON_NONCEBYTES to a buffer, reversing its byte order
+
+   To maintain compability with pre-v11 versions, which used a little-endian nonce,
+   the xsalsa20-poly1305 keeps using the old nonce format.
+*/
 static inline void memcpy_nonce(uint8_t *dst, const uint8_t *src) {
 	size_t i;
 	for (i = 0; i < COMMON_NONCEBYTES; i++)
 		dst[i] = src[COMMON_NONCEBYTES-i-1];
 }
 
+/** Adds the xsalsa20-poly1305 header to the head of a packet */
 static inline void put_header(fastd_buffer_t *buffer, const uint8_t nonce[COMMON_NONCEBYTES], uint8_t flags) {
 	fastd_buffer_pull_head_from(buffer, &flags, 1);
 
@@ -103,19 +131,22 @@ static inline void put_header(fastd_buffer_t *buffer, const uint8_t nonce[COMMON
 	memcpy_nonce(buffer->data, nonce);
 }
 
+/** Removes the xsalsa20-poly1305 header from the head of a packet */
 static inline void take_header(fastd_buffer_t *buffer, uint8_t nonce[COMMON_NONCEBYTES], uint8_t *flags) {
-	memcpy_nonce(nonce, buffer->data  );
+	memcpy_nonce(nonce, buffer->data);
 	fastd_buffer_push_head(buffer, COMMON_NONCEBYTES);
 
 	fastd_buffer_push_head_to(buffer, flags, 1);
 }
 
+/** Removes and handles the xsalsa20-poly1305 header from the head of a packet */
 static inline bool handle_header(const fastd_method_common_t *session, fastd_buffer_t *buffer, uint8_t nonce[COMMON_NONCEBYTES], uint8_t *flags, int64_t *age) {
 	take_header(buffer, nonce, flags);
 	return fastd_method_is_nonce_valid(session, nonce, age);
 }
 
 
+/** Performs encryption and authentication of a packet */
 static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	fastd_buffer_pull_head_zero(&in, crypto_secretbox_xsalsa20poly1305_ZEROBYTES);
 
@@ -135,6 +166,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state
 	return true;
 }
 
+/** Performs validation and decryption of a packet */
 static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) {
 	if (in.len < COMMON_HEADBYTES)
 		return false;
@@ -180,6 +212,7 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses
 }
 
 
+/** The xsalsa20-poly1305 method provider */
 const fastd_method_provider_t fastd_method_xsalsa20_poly1305 = {
 
 	.max_overhead = COMMON_HEADBYTES + crypto_secretbox_xsalsa20poly1305_ZEROBYTES - crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES,