mtcp_getlastpkt - Retrieves the last Ethernet frame of a monitoring flow #include <mos_api.h> "int mtcp_getlastpkt(mctx_t " mctx ", int " sockid ", int " side ", struct pkt_info *" pinfo ); mtcp_getlastpkt () fetches a copy of the last Ethernet frame for a given flow observed by the stack. The user can select the socket descriptor using "sockid" and the "side" argument (MOS_SIDE_CLI or MOS_SIDE_SVR) to fetch the Ethernet frame of her choosing. "pinfo" points to an instance of struct pkt_info that should be allocated by the user before calling the function. The structure is defined as:

struct pkt_info { // pkt recving time uint32_t cur_ts; // ETH uint16_t eth_len; // IP uint16_t ip_len; //TCP uint64_t offset; // TCP recv buffer offset uint16_t payloadlen; uint32_t seq; uint32_t ack_seq; uint16_t window; struct ethhdr *ethh; struct iphdr *iph; struct tcphdr *tcph; uint8_t *payload; }

A successful call to mtcp_getlastpkt() creates a copy of the last recorded Ethernet frame and appends its meta-data (in host byte order). The last four fields of "pinfo" (ethh, iph, tcph and payload) point to the copied frame at the appropriate offsets. Please note that the packet buffer that contains the copied frame is reused for future invocations of mtcp_getlastpkt(). An mtcp_getlastpkt () call takes an additional argument named "mctx" that represents 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. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

15 "EACCES" "mctx" is invalid.

15 "EPERM" Permission denied.

15 "ENODATA" The last captured Ethernet frame for this flow does not exist. This can occur if "mtcp_getlastpkt()" is called during e.g. connection initiation.

15 "EBADF" "sockid" is not a valid socket descriptor for creating a connection. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
"""".SH CONFORMING TO
""""POSIX.1-2001.
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mOS development team <[email protected]> """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
mtcp_create_context (), mtcp_setlastpkt (), mtcp_socket (), """""""""""""""""""""""""""""""""""""""""""""""""""""
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/. """""""""""""""""""""""""""""""""""""""""""""""""""""