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* strparser: Propagate correct error code in strp_recv()Geert Uytterhoeven2016-10-121-1/+1
| | | | | | | | | | | | | | With m68k-linux-gnu-gcc-4.1: net/strparser/strparser.c: In function ‘strp_recv’: net/strparser/strparser.c:98: warning: ‘err’ may be used uninitialized in this function Pass "len" (which is an error code when negative) instead of the uninitialized "err" variable to fix this. Fixes: 43a0c6751a322847 ("strparser: Stream parser for messages") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* kcm: Remove TCP specific references from kcm and strparserTom Herbert2016-08-281-19/+29
| | | | | | | | | | kcm and strparser need to work with any type of stream socket not just TCP. Eliminate references to TCP and call generic proto_ops functions of read_sock and peek_len. Also in strp_init check if the socket support the proto_ops read_sock and peek_len. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Queue work when being unpausedTom Herbert2016-08-231-0/+11
| | | | | | | | When the upper layer unpauses a stream parser connection we need to queue rx_work to make sure no events are missed. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: strparser: fix strparser sk_user_data checkDave Watson2016-08-221-3/+0
| | | | | | | | | | | | sk_user_data mismatch between what kcm expects (psock) and what strparser expects (strparser). Queued rx_work, for example calling strp_check_rcv after socket buffer changes, will never complete. sk_user_data is unused in strparser, so just remove the check. Signed-off-by: Dave Watson <davejwatson@fb.com> Acked-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* strparser: Stream parser for messagesTom Herbert2016-08-173-0/+497
This patch introduces a utility for parsing application layer protocol messages in a TCP stream. This is a generalization of the mechanism implemented of Kernel Connection Multiplexor. The API includes a context structure, a set of callbacks, utility functions, and a data ready function. A stream parser instance is defined by a strparse structure that is bound to a TCP socket. The function to initialize the structure is: int strp_init(struct strparser *strp, struct sock *csk, struct strp_callbacks *cb); csk is the TCP socket being bound to and cb are the parser callbacks. The upper layer calls strp_tcp_data_ready when data is ready on the lower socket for strparser to process. This should be called from a data_ready callback that is set on the socket: void strp_tcp_data_ready(struct strparser *strp); A parser is bound to a TCP socket by setting data_ready function to strp_tcp_data_ready so that all receive indications on the socket go through the parser. This is assumes that sk_user_data is set to the strparser structure. There are four callbacks. - parse_msg is called to parse the message (returns length or error). - rcv_msg is called when a complete message has been received - read_sock_done is called when data_ready function exits - abort_parser is called to abort the parser The input to parse_msg is an skbuff which contains next message under construction. The backend processing of parse_msg will parse the application layer protocol headers to determine the length of the message in the stream. The possible return values are: >0 : indicates length of successfully parsed message 0 : indicates more data must be received to parse the message -ESTRPIPE : current message should not be processed by the kernel, return control of the socket to userspace which can proceed to read the messages itself other < 0 : Error is parsing, give control back to userspace assuming that synchronzation is lost and the stream is unrecoverable (application expected to close TCP socket) In the case of error return (< 0) strparse will stop the parser and report and error to userspace. The application must deal with the error. To handle the error the strparser is unbound from the TCP socket. If the error indicates that the stream TCP socket is at recoverable point (ESTRPIPE) then the application can read the TCP socket to process the stream. Once the application has dealt with the exceptions in the stream, it may again bind the socket to a strparser to continue data operations. Note that ENODATA may be returned to the application. In this case parse_msg returned -ESTRPIPE, however strparser was unable to maintain synchronization of the stream (i.e. some of the message in question was already read by the parser). strp_pause and strp_unpause are used to provide flow control. For instance, if rcv_msg is called but the upper layer can't immediately consume the message it can hold the message and pause strparser. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>