mtcp_getsockopt - get options on mTCP/mOS sockets #include <mtcp_api.h> "int mtcp_getsockopt(mctx_t " mctx ", int " sockid ", int " level ", int " optname ", const void *" optval ", socklen_t *" optlen ); mtcp_getsockopt () manipulate options for the socket referred to by the "sockid" descriptor. These options may exist at multiple protocol levels. When manipulating socket options, the level at which the options resides and the name of the option must be specified. A user can use "SOL_SOCKET" "level" to adjust these options for mTCP endpoint applications; while "SOL_MONSOCKET" "level" can be used to adjust options for monitoring sockets. For mtcp_getsockopt() "optval" identifies the buffer in which the value for the requested option is to be returned and the "optlen" argument is updated to indicate the actual size of the "optval" returned. It is the user's responsibility to allocate memory for both "optval" and "optlen" arguments. At the moment, mOS only provides one "optname" named "SO_ERROR" that can only be used for mtcp_getsockopt() function for SOL_SOCKET socket "level" . A successful execution of this function call with the specified option name returns the most recently recorded socket error for the particular connection (specific to the "sockid" socket descriptor). SOL_MONSOCKET socket level can be used by mtcp_getsockopt() to retrieve a number of socket options.

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Gives back offsets to fragments (non-contiguous data segments) currently stored in client's TCP ring buffer. The optval is an array of struct tcp_ring_fragment which is defined as: struct tcp_ring_fragment { uint64_t offset; uint32_t len; } where offset flow data starting from client's TCP SYN sequence number, and len is the length of the tcp_ring_fragment. The optval holds the size of the array (in terms of the number of elements). Gives back offsets to fragments (non-contiguous data segments) currently stored in server's TCP ring buffer. The optval is the array of struct tcp_ring_fragment where offset flow data starting from server's TCP SYN sequence number, and len is the length of the tcp_ring_fragment. The optlen holds the size of the array (in terms of the number of elements). Returns meta-data regarding the client's TCP ring buffer. This information is returned in the form of optval which is passed as struct tcp_buf_info. struct tcp_buf_info { /* The initial TCP sequence number of TCP ring buffer. */ uint32_t tcpbi_init_seq; /* TCP sequence number of the 'last byte of payload that has already been read by the end application' (applies in the case of embedded monitor setup) */ uint32_t tcpbi_last_byte_read; /* TCP sequence number of the 'last byte of the payload that is currently buffered and needs to be read by the end application' (applies in the case of embedded monitor setup). In case of standalone monitors, tcpbi_last_byte_read = tcpbi_next_byte_expected */ uint32_t tcpbi_next_byte_expected; /* TCP sequence number of the 'last byte of the payload that is currently stored' in the TCP ring buffer. This value may be greater than tcpbi_next_byte_expected if packets arrive out of order. */ uint32_t tcpbi_last_byte_received; } The optlen value contains the sizeof(struct tcp_buf_info). Returns meta-data regarding the server's TCP ring buffer. This information is returned in the form of optval which is passed as struct tcp_buf_info. The optlen value contains the sizeof(struct tcp_buf_info). Returns the current emulated state of the client. The optval argument is a pointer to an int whereas the optlen argument contains the sizeof(int). The optval returns a value of type enum tcpstate which can carry any one of the following states. enum tcpstate { TCP_CLOSED = 0, TCP_LISTEN, TCP_SYN_SENT, TCP_SYN_RCVD, TCP_ESTABLISHED, TCP_FIN_WAIT_1, TCP_FINE_WAIT_2, TCP_CLOSE_WAIT, TCP_CLOSING, TCP_LAST_ACK, TCP_TIME_WAIT } Returns the current emulated state of the server. The optval argument is a pointer to an int whereas the optlen argument contains the sizeof(int). The optval returns a value of type enum tcpstate.

Both the functions take an additional argument named "mctx" that represent the per-core mTCP context in an application (see mtcp_create_context() for details). """""""""""""""""""""""""""""""""""""""""""""""""""""""""""

Returns 0 on success; -1 on failure. In case of failure, "errno" is set appropriately. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

10 "EACCES" "mctx" is not valid.

10 "EBADF" "sockid" is not a valid socket descriptor.

10 "ENOTSOCK" The socket referred to by "sockid" is not valid.

10 "ENOSYS" Either the "level" or the "optname" is not implemented.

10 "EPERM" Permission to access a socket option is denied.

10 """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
"""".SH CONFORMING TO
""""POSIX.1-2001.
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mOS development team <[email protected]> """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
mtcp_socket (), mtcp_setsockopt () """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
This page is part of mOS release 0.3 "docs" section. A description of the project, and information about reporting bugs, can be found at \%http://mos.kaist.edu/. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""