From e09ca3d9b68486fa9a4c368fd6578c68fc54c242 Mon Sep 17 00:00:00 2001 From: Hanno Becker Date: Mon, 22 May 2017 15:06:06 +0100 Subject: [PATCH] Add polling function for network contexts This commit adds a function `mbedtls_net_poll` to the network module allowing to check if a network context is available for read or write. --- include/mbedtls/net_sockets.h | 28 ++++++++++++++++++ library/error.c | 4 +++ library/net_sockets.c | 56 +++++++++++++++++++++++++++++++++-- 3 files changed, 86 insertions(+), 2 deletions(-) diff --git a/include/mbedtls/net_sockets.h b/include/mbedtls/net_sockets.h index de335526f..2777b79e4 100644 --- a/include/mbedtls/net_sockets.h +++ b/include/mbedtls/net_sockets.h @@ -45,12 +45,17 @@ #define MBEDTLS_ERR_NET_UNKNOWN_HOST -0x0052 /**< Failed to get an IP address for the given hostname. */ #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL -0x0043 /**< Buffer is too small to hold the data. */ #define MBEDTLS_ERR_NET_INVALID_CONTEXT -0x0045 /**< The context is invalid, eg because it was free()ed. */ +#define MBEDTLS_ERR_NET_POLL_FAILED -0x0047 /**< Polling the net context failed. */ +#define MBEDTLS_ERR_NET_BAD_INPUT_DATA -0x0049 /**< Input invalid. */ #define MBEDTLS_NET_LISTEN_BACKLOG 10 /**< The backlog that listen() should use. */ #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */ #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */ +#define MBEDTLS_NET_POLL_READ 1 /**< Used in \c mbedtls_net_poll to check for pending data */ +#define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */ + #ifdef __cplusplus extern "C" { #endif @@ -131,6 +136,29 @@ int mbedtls_net_accept( mbedtls_net_context *bind_ctx, mbedtls_net_context *client_ctx, void *client_ip, size_t buf_size, size_t *ip_len ); +/** + * \brief Check and wait for the context to be ready for read/write + * + * \param ctx Socket to check + * \param rw Bitflag composed of MBEDTLS_NET_POLL_READ and + * MBEDTLS_NET_POLL_WRITE specifying the events + * to wait for: + * - If MBEDTLS_NET_POLL_READ is set, the function + * will return as soon as the net context is available + * for reading. + * - If MBEDTLS_NET_POLL_WRITE is set, the function + * will return as soon as the net context is available + * for writing. + * \param timeout Maximal amount of time to wait before returning, + * in milliseconds. If \c timeout is zero, the + * function returns immediately. If \c timeout is + * -1u, the function blocks potentially indefinitely. + * + * \return Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE + * on success or timeout, or a negative return code otherwise. + */ +int mbedtls_net_poll( mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout ); + /** * \brief Set the socket blocking * diff --git a/library/error.c b/library/error.c index db42381c4..8977cc4e5 100644 --- a/library/error.c +++ b/library/error.c @@ -654,6 +654,10 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen ) mbedtls_snprintf( buf, buflen, "NET - Buffer is too small to hold the data" ); if( use_ret == -(MBEDTLS_ERR_NET_INVALID_CONTEXT) ) mbedtls_snprintf( buf, buflen, "NET - The context is invalid, eg because it was free()ed" ); + if( use_ret == -(MBEDTLS_ERR_NET_POLL_FAILED) ) + mbedtls_snprintf( buf, buflen, "NET - Polling the net context failed" ); + if( use_ret == -(MBEDTLS_ERR_NET_BAD_INPUT_DATA) ) + mbedtls_snprintf( buf, buflen, "NET - Input invalid" ); #endif /* MBEDTLS_NET_C */ #if defined(MBEDTLS_OID_C) diff --git a/library/net_sockets.c b/library/net_sockets.c index 80be6ec6a..edd084416 100644 --- a/library/net_sockets.c +++ b/library/net_sockets.c @@ -433,6 +433,58 @@ int mbedtls_net_set_nonblock( mbedtls_net_context *ctx ) #endif } +/* + * Check if data is available on the socket + */ + +int mbedtls_net_poll( mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout ) +{ + int ret; + struct timeval tv; + + fd_set read_fds; + fd_set write_fds; + + int fd = ctx->fd; + + if( fd < 0 ) + return( MBEDTLS_ERR_NET_INVALID_CONTEXT ); + + FD_ZERO( &read_fds ); + if( rw & MBEDTLS_NET_POLL_READ ) + { + rw &= ~MBEDTLS_NET_POLL_READ; + FD_SET( fd, &read_fds ); + } + + FD_ZERO( &write_fds ); + if( rw & MBEDTLS_NET_POLL_WRITE ) + { + rw &= ~MBEDTLS_NET_POLL_WRITE; + FD_SET( fd, &write_fds ); + } + + if( rw != 0 ) + return( MBEDTLS_ERR_NET_BAD_INPUT_DATA ); + + tv.tv_sec = timeout / 1000; + tv.tv_usec = ( timeout % 1000 ) * 1000; + + ret = select( fd + 1, &read_fds, &write_fds, NULL, + timeout == (uint32_t) -1u ? NULL : &tv ); + + if( ret < 0 ) + return( MBEDTLS_ERR_NET_POLL_FAILED ); + + ret = 0; + if( FD_ISSET( fd, &read_fds ) ) + ret |= MBEDTLS_NET_POLL_READ; + if( FD_ISSET( fd, &write_fds ) ) + ret |= MBEDTLS_NET_POLL_WRITE; + + return( ret ); +} + /* * Portable usleep helper */ @@ -492,8 +544,8 @@ int mbedtls_net_recv( void *ctx, unsigned char *buf, size_t len ) /* * Read at most 'len' characters, blocking for at most 'timeout' ms */ -int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, size_t len, - uint32_t timeout ) +int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, + size_t len, uint32_t timeout ) { int ret; struct timeval tv;