API: add lsquic_conn_get_sni(), fixes issue #203

bin/http_server.c

@@ -321,6 +321,11 @@ static lsquic_conn_ctx_t *
 http_server_on_new_conn (void *stream_if_ctx, lsquic_conn_t *conn)
 {
     struct server_ctx *server_ctx = stream_if_ctx;
+    const char *sni;
+
+    sni = lsquic_conn_get_sni(conn);
+    LSQ_DEBUG("new connection, SNI: %s", sni ? sni : "<not set>");
+
     lsquic_conn_ctx_t *conn_h = malloc(sizeof(*conn_h));
     conn_h->conn = conn;
     conn_h->server_ctx = server_ctx;

docs/apiref.rst

@@ -1964,6 +1964,10 @@ Miscellaneous Connection Functions
 
     Get peer context associated with the connection and local address.
 
+.. function:: const char * lsquic_conn_get_sni (lsquic_conn_t *conn)
+
+    Get SNI sent by the client.
+
 .. function:: enum LSQUIC_CONN_STATUS lsquic_conn_status (lsquic_conn_t *conn, char *errbuf, size_t bufsz)
 
     Get connection status.

include/lsquic.h

@@ -1979,6 +1979,10 @@ lsquic_conn_set_ctx (lsquic_conn_t *, lsquic_conn_ctx_t *);
 void *
 lsquic_conn_get_peer_ctx (lsquic_conn_t *, const struct sockaddr *local_sa);
 
+/** Get SNI sent by the client */
+const char *
+lsquic_conn_get_sni (lsquic_conn_t *);
+
 /**
  * Abort connection.
  */

src/liblsquic/lsquic_conn.c

@@ -324,3 +324,13 @@ lsquic_conn_stats_diff (const struct conn_stats *cumulative_stats,
 
 
 #endif
+
+
+const char *
+lsquic_conn_get_sni (struct lsquic_conn *lconn)
+{
+    if (lconn->cn_esf_c && lconn->cn_esf_c->esf_get_sni)
+        return lconn->cn_esf_c->esf_get_sni(lconn->cn_enc_session);
+    else
+        return NULL;
+}

src/liblsquic/lsquic_enc_sess.h

@@ -99,6 +99,9 @@ struct enc_session_funcs_common
     int
     (*esf_alg_keysize) (enc_session_t *);
 
+    const char *
+    (*esf_get_sni) (enc_session_t *);
+
     /* Need to pass lconn in encrypt and decrypt methods because enc_session
      * is allowed to be NULL for gQUIC.
      */

src/liblsquic/lsquic_enc_sess_ietf.c

@@ -2410,6 +2410,21 @@ iquic_esf_decrypt_packet (enc_session_t *enc_session_p,
 }
 
 
+static const char *
+iquic_esf_get_sni (enc_session_t *enc_session_p)
+{
+    struct enc_sess_iquic *const enc_sess = enc_session_p;
+    const char *server_name;
+
+    server_name = SSL_get_servername(enc_sess->esi_ssl, TLSEXT_NAMETYPE_host_name);
+#ifndef NDEBUG
+    if (!server_name)
+        server_name = enc_sess->esi_sni_bypass;
+#endif
+    return server_name;
+}
+
+
 static int
 iquic_esf_global_init (int flags)
 {
@@ -2669,6 +2684,7 @@ const struct enc_session_funcs_common lsquic_enc_session_common_ietf_v1 =
     .esf_tag_len         = IQUIC_TAG_LEN,
     .esf_get_server_cert_chain
                          = iquic_esf_get_server_cert_chain,
+    .esf_get_sni         = iquic_esf_get_sni,
     .esf_cipher          = iquic_esf_cipher,
     .esf_keysize         = iquic_esf_keysize,
     .esf_alg_keysize     = iquic_esf_alg_keysize,
@@ -2687,6 +2703,7 @@ const struct enc_session_funcs_common lsquic_enc_session_common_ietf_v1_no_flush
     .esf_tag_len         = IQUIC_TAG_LEN,
     .esf_get_server_cert_chain
                          = iquic_esf_get_server_cert_chain,
+    .esf_get_sni         = iquic_esf_get_sni,
     .esf_cipher          = iquic_esf_cipher,
     .esf_keysize         = iquic_esf_keysize,
     .esf_alg_keysize     = iquic_esf_alg_keysize,

src/liblsquic/lsquic_handshake.c

@@ -3502,6 +3502,14 @@ lsquic_enc_session_get_ua (enc_session_t *enc_session_p)
 }
 
 
+static const char *
+lsquic_enc_session_get_sni (enc_session_t *enc_session_p)
+{
+    struct lsquic_enc_session *const enc_session = enc_session_p;
+    return lsquic_str_cstr(&enc_session->hs_ctx.sni);
+}
+
+
 #ifndef NDEBUG
 static uint8_t
 lsquic_enc_session_have_key (enc_session_t *enc_session_p)
@@ -3819,6 +3827,7 @@ struct enc_session_funcs_common lsquic_enc_session_common_gquic_1 =
     .esf_cipher = lsquic_enc_session_cipher,
     .esf_keysize = lsquic_enc_session_keysize,
     .esf_alg_keysize = lsquic_enc_session_alg_keysize,
+    .esf_get_sni = lsquic_enc_session_get_sni,
     .esf_encrypt_packet = gquic_encrypt_packet,
     .esf_decrypt_packet = gquic_decrypt_packet,
     .esf_tag_len = GQUIC_PACKET_HASH_SZ,
@@ -4246,6 +4255,7 @@ const
 /* Q050 and later */
 struct enc_session_funcs_common lsquic_enc_session_common_gquic_2 =
 {
+    .esf_get_sni                =  lsquic_enc_session_get_sni,
     .esf_global_init            =  lsquic_handshake_init,
     .esf_global_cleanup         =  lsquic_handshake_cleanup,
     .esf_cipher                 =  lsquic_enc_session_cipher,