server session FEATURE callhome

Only SSH settings implemented,
the rest as prototypes only.
diff --git a/src/session_server.h b/src/session_server.h
index aa72311..6c74e07 100644
--- a/src/session_server.h
+++ b/src/session_server.h
@@ -244,6 +244,8 @@
  */
 int nc_accept(int timeout, struct nc_session **session);
 
+int nc_connect_callhome(const char *host, uint16_t port, NC_TRANSPORT_IMPL ti, int timeout, struct nc_session **session);
+
 #endif /* ENABLE_SSH || ENABLE_TLS */
 
 #ifdef ENABLE_SSH
@@ -319,8 +321,73 @@
  */
 int nc_ssh_server_del_authkey(const char *pubkey_path, const char *username);
 
+/*
+ * Call Home
+ */
+
 /**
- * @brief Free all the various SSH server options.
+ * @brief Set Call Home SSH host keys the server will identify itself with. Each of RSA, DSA, and
+ * ECDSA keys can be set. If the particular type was already set, it is replaced.
+ *
+ * @param[in] privkey_path Path to a private key.
+ * @return 0 on success, -1 on error.
+ */
+int nc_ssh_server_ch_set_hostkey(const char *privkey_path);
+
+/**
+ * @brief Set Call Home SSH banner the server will send to every client.
+ *
+ * @param[in] banner SSH banner.
+ * @return 0 on success, -1 on error.
+ */
+int nc_ssh_server_ch_set_banner(const char *banner);
+
+/**
+ * @brief Set accepted Call Home SSH authentication methods. All (publickey, password, interactive)
+ * are supported by default.
+ *
+ * @param[in] auth_methods Accepted authentication methods bit field of NC_SSH_AUTH_TYPE.
+ * @return 0 on success, -1 on error.
+ */
+int nc_ssh_server_ch_set_auth_methods(int auth_methods);
+
+/**
+ * @brief Set Call Home SSH authentication attempts of every client. 3 by default.
+ *
+ * @param[in] auth_attempts Failed authentication attempts before a client is dropped.
+ * @return 0 on success, -1 on error.
+ */
+int nc_ssh_server_ch_set_auth_attempts(uint16_t auth_attempts);
+
+/**
+ * @brief Set Call Home SSH authentication timeout. 10 seconds by default.
+ *
+ * @param[in] auth_timeout Number of seconds before an unauthenticated client is dropped.
+ * @return 0 on success, -1 on error.
+ */
+int nc_ssh_server_ch_set_auth_timeout(uint16_t auth_timeout);
+
+/**
+ * @brief Add an authorized Call Home client SSH public key. This public key can be used for
+ * publickey authentication afterwards.
+ *
+ * @param[in] pubkey_path Path to the public key.
+ * @param[in] username Username that the client with the public key must use.
+ * @return 0 on success, -1 on error.
+ */
+int nc_ssh_server_ch_add_authkey(const char *pubkey_path, const char *username);
+
+/**
+ * @brief Remove an authorized Call Home client SSH public key.
+ *
+ * @param[in] pubkey_path Path to an authorized public key. NULL matches all the keys.
+ * @param[in] username Username for an authorized public key. NULL matches all the usernames.
+ * @return 0 on success, -1 on not finding any match.
+ */
+int nc_ssh_server_ch_del_authkey(const char *pubkey_path, const char *username);
+
+/**
+ * @brief Free all the various SSH server options (including Call Home ones).
  */
 void nc_ssh_server_free_opts(void);
 
@@ -440,8 +507,124 @@
  */
 int nc_tls_server_del_ctn(int64_t id, const char *fingerprint, NC_TLS_CTN_MAPTYPE map_type, const char *name);
 
+/*
+ * Call Home
+ */
+
 /**
- * @brief Free all the various TLS server options.
+ * @brief Set server Call Home TLS certificate. Alternative to nc_tls_server_set_cert_path().
+ * There can only be one certificate for each key type, it is replaced if already set.
+ *
+ * @param[in] cert Base64-encoded certificate in ASN.1 DER encoding.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_set_cert(const char *cert);
+
+/**
+ * @brief Set server Call Home TLS certificate. Alternative to nc_tls_server_set_cert().
+ * There can only be one certificate for each key type, it is replaced if already set.
+ *
+ * @param[in] cert_path Path to a certificate file in PEM format.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_set_cert_path(const char *cert_path);
+
+/**
+ * @brief Set server Call Home TLS private key matching the certificate.
+ * Alternative to nc_tls_server_set_key_path(). There can only be one of every key
+ * type, it is replaced if already set.
+ *
+ * @param[in] privkey Base64-encoded certificate in ASN.1 DER encoding.
+ * @param[in] is_rsa Whether \p privkey are the data of an RSA (1) or DSA (0) key.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_set_key(const char *privkey, int is_rsa);
+
+/**
+ * @brief Set server Call Home TLS private key matching the certificate.
+ * Alternative to nc_tls_server_set_key_path(). There can only be one of every key
+ * type, it is replaced if already set.
+ *
+ * @param[in] privkey_path Path to a private key file in PEM format.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_set_key_path(const char *privkey_path);
+
+/**
+ * @brief Add a Call Home trusted certificate. Can be both a CA or a client one.
+ *
+ * @param[in] cert Base64-enocded certificate in ASN.1DER encoding.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_add_trusted_cert(const char *cert);
+
+/**
+ * @brief Add a Call Home trusted certificate. Can be both a CA or a client one.
+ *
+ * @param[in] cert_path Path to a trusted certificate file in PEM format.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_add_trusted_cert_path(const char *cert_path);
+
+/**
+ * @brief Set trusted Call Home Certificate Authority certificate locations. There
+ * can only be one file and one directory, they are replaced if already set.
+ *
+ * @param[in] cacert_file_path Path to a trusted CA cert store file in PEM format.
+ * Can be NULL.
+ * @param[in] cacert_dir_path Path to a trusted CA cert store hashed directory
+ * (c_rehash utility can be used to create hashes) with PEM files. Can be NULL.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_set_trusted_cacert_locations(const char *cacert_file_path, const char *cacert_dir_path);
+
+/**
+ * @brief Destroy and clean all the set Call Home certificates and private keys.
+ * CRLs and CTN entries are not affected.
+ */
+void nc_tls_server_ch_destroy_certs(void);
+
+/**
+ * @brief Set Call Home Certificate Revocation List locations. There can only be
+ * one file and one directory, they are replaced if already set.
+ *
+ * @param[in] crl_file_path Path to a CRL store file in PEM format. Can be NULL.
+ * @param[in] crl_dir_path Path to a CRL store hashed directory (c_rehash utility
+ * can be used to create hashes) with PEM files. Can be NULL.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_set_crl_locations(const char *crl_file_path, const char *crl_dir_path);
+
+/**
+ * @brief Destroy and clean Call Home CRLs. Call Home certificates, private keys,
+ * and CTN entries are not affected.
+ */
+void nc_tls_server_ch_destroy_crls(void);
+
+/**
+ * @brief Add a Call Home Cert-to-name entry.
+ *
+ * @param[in] id Priority of the entry.
+ * @param[in] fingerprint Matching certificate fingerprint.
+ * @param[in] map_type Type of username-certificate mapping.
+ * @param[in] name Specific username if \p map_type == NC_TLS_CTN_SPECIFED. Must be NULL otherwise.
+ * @return 0 on success, -1 on error.
+ */
+int nc_tls_server_ch_add_ctn(uint32_t id, const char *fingerprint, NC_TLS_CTN_MAPTYPE map_type, const char *name);
+
+/**
+ * @brief Remove a Call Home Cert-to-name entry.
+ *
+ * @param[in] id Priority of the entry. -1 matches all the priorities.
+ * @param[in] fingerprint Fingerprint fo the entry. NULL matches all the fingerprints.
+ * @param[in] map_type Mapping type of the entry. 0 matches all the mapping types.
+ * @param[in] name Specific username for the entry. NULL matches all the usernames.
+ * @return 0 on success, -1 on not finding any match.
+ */
+int nc_tls_server_ch_del_ctn(int64_t id, const char *fingerprint, NC_TLS_CTN_MAPTYPE map_type, const char *name);
+
+/**
+ * @brief Free all the various TLS server options (including Call Home ones).
  */
 void nc_tls_server_free_opts(void);