| /* |
| * include/haproxy/channel-t.h |
| * Channel management definitions, macros and inline functions. |
| * |
| * Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation, version 2.1 |
| * exclusively. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef _HAPROXY_CHANNEL_T_H |
| #define _HAPROXY_CHANNEL_T_H |
| |
| #include <haproxy/api-t.h> |
| #include <haproxy/buf-t.h> |
| |
| /* The CF_* macros designate Channel Flags, which may be ORed in the bit field |
| * member 'flags' in struct channel. Here we have several types of flags : |
| * |
| * - pure status flags, reported by the data layer, which must be cleared |
| * before doing further I/O : |
| * CF_*_NULL, CF_*_PARTIAL |
| * |
| * - pure status flags, reported by stream-interface layer, which must also |
| * be cleared before doing further I/O : |
| * CF_*_TIMEOUT, CF_*_ERROR |
| * |
| * - read-only indicators reported by lower data levels : |
| * CF_STREAMER, CF_STREAMER_FAST |
| * |
| * - write-once status flags reported by the stream-interface layer : |
| * CF_SHUTR, CF_SHUTW |
| * |
| * - persistent control flags managed only by application level : |
| * CF_SHUT*_NOW, CF_*_ENA |
| * |
| * The flags have been arranged for readability, so that the read and write |
| * bits have the same position in a byte (read being the lower byte and write |
| * the second one). All flag names are relative to the channel. For instance, |
| * 'write' indicates the direction from the channel to the stream interface. |
| */ |
| |
| #define CF_READ_NULL 0x00000001 /* last read detected on producer side */ |
| #define CF_READ_PARTIAL 0x00000002 /* some data were read from producer or a read exception occurred */ |
| #define CF_READ_TIMEOUT 0x00000004 /* timeout while waiting for producer */ |
| #define CF_READ_ERROR 0x00000008 /* unrecoverable error on producer side */ |
| #define CF_READ_ACTIVITY (CF_READ_NULL|CF_READ_PARTIAL|CF_READ_ERROR) |
| |
| /* unused: 0x00000010 */ |
| #define CF_SHUTR 0x00000020 /* producer has already shut down */ |
| #define CF_SHUTR_NOW 0x00000040 /* the producer must shut down for reads ASAP */ |
| #define CF_READ_NOEXP 0x00000080 /* producer should not expire */ |
| |
| #define CF_WRITE_NULL 0x00000100 /* write(0) or connect() succeeded on consumer side */ |
| #define CF_WRITE_PARTIAL 0x00000200 /* some data were written to the consumer */ |
| #define CF_WRITE_TIMEOUT 0x00000400 /* timeout while waiting for consumer */ |
| #define CF_WRITE_ERROR 0x00000800 /* unrecoverable error on consumer side */ |
| #define CF_WRITE_ACTIVITY (CF_WRITE_NULL|CF_WRITE_PARTIAL|CF_WRITE_ERROR) |
| |
| #define CF_WAKE_WRITE 0x00001000 /* wake the task up when there's write activity */ |
| #define CF_SHUTW 0x00002000 /* consumer has already shut down */ |
| #define CF_SHUTW_NOW 0x00004000 /* the consumer must shut down for writes ASAP */ |
| #define CF_AUTO_CLOSE 0x00008000 /* producer can forward shutdown to other side */ |
| |
| /* When CF_SHUTR_NOW is set, it is strictly forbidden for the producer to alter |
| * the buffer contents. When CF_SHUTW_NOW is set, the consumer is free to perform |
| * a shutw() when it has consumed the last contents, otherwise the session processor |
| * will do it anyway. |
| * |
| * The SHUT* flags work like this : |
| * |
| * SHUTR SHUTR_NOW meaning |
| * 0 0 normal case, connection still open and data is being read |
| * 0 1 closing : the producer cannot feed data anymore but can close |
| * 1 0 closed: the producer has closed its input channel. |
| * 1 1 impossible |
| * |
| * SHUTW SHUTW_NOW meaning |
| * 0 0 normal case, connection still open and data is being written |
| * 0 1 closing: the consumer can send last data and may then close |
| * 1 0 closed: the consumer has closed its output channel. |
| * 1 1 impossible |
| * |
| * The SHUTW_NOW flag should be set by the session processor when SHUTR and AUTO_CLOSE |
| * are both set. And it may also be set by the producer when it detects SHUTR while |
| * directly forwarding data to the consumer. |
| * |
| * The SHUTR_NOW flag is mostly used to force the producer to abort when an error is |
| * detected on the consumer side. |
| */ |
| |
| #define CF_STREAMER 0x00010000 /* the producer is identified as streaming data */ |
| #define CF_STREAMER_FAST 0x00020000 /* the consumer seems to eat the stream very fast */ |
| |
| #define CF_WROTE_DATA 0x00040000 /* some data were sent from this buffer */ |
| #define CF_ANA_TIMEOUT 0x00080000 /* the analyser timeout has expired */ |
| #define CF_READ_ATTACHED 0x00100000 /* the read side is attached for the first time */ |
| #define CF_KERN_SPLICING 0x00200000 /* kernel splicing desired for this channel */ |
| #define CF_READ_DONTWAIT 0x00400000 /* wake the task up after every read (eg: HTTP request) */ |
| #define CF_AUTO_CONNECT 0x00800000 /* consumer may attempt to establish a new connection */ |
| |
| #define CF_DONT_READ 0x01000000 /* disable reading for now */ |
| #define CF_EXPECT_MORE 0x02000000 /* more data expected to be sent very soon (one-shoot) */ |
| #define CF_SEND_DONTWAIT 0x04000000 /* don't wait for sending data (one-shoot) */ |
| #define CF_NEVER_WAIT 0x08000000 /* never wait for sending data (permanent) */ |
| |
| #define CF_WAKE_ONCE 0x10000000 /* pretend there is activity on this channel (one-shoot) */ |
| #define CF_FLT_ANALYZE 0x20000000 /* at least one filter is still analyzing this channel */ |
| #define CF_EOI 0x40000000 /* end-of-input has been reached */ |
| #define CF_ISRESP 0x80000000 /* 0 = request channel, 1 = response channel */ |
| |
| /* Masks which define input events for stream analysers */ |
| #define CF_MASK_ANALYSER (CF_READ_ATTACHED|CF_READ_ACTIVITY|CF_READ_TIMEOUT|CF_ANA_TIMEOUT|CF_WRITE_ACTIVITY|CF_WAKE_ONCE) |
| |
| /* Mask for static flags which cause analysers to be woken up when they change */ |
| #define CF_MASK_STATIC (CF_SHUTR|CF_SHUTW|CF_SHUTR_NOW|CF_SHUTW_NOW) |
| |
| |
| /* Analysers (channel->analysers). |
| * Those bits indicate that there are some processing to do on the buffer |
| * contents. It will probably evolve into a linked list later. Those |
| * analysers could be compared to higher level processors. |
| * The field is blanked by channel_init() and only by analysers themselves |
| * afterwards. |
| */ |
| /* AN_REQ_FLT_START_FE: 0x00000001 */ |
| #define AN_REQ_INSPECT_FE 0x00000002 /* inspect request contents in the frontend */ |
| #define AN_REQ_WAIT_HTTP 0x00000004 /* wait for an HTTP request */ |
| #define AN_REQ_HTTP_BODY 0x00000008 /* wait for HTTP request body */ |
| #define AN_REQ_HTTP_PROCESS_FE 0x00000010 /* process the frontend's HTTP part */ |
| #define AN_REQ_SWITCHING_RULES 0x00000020 /* apply the switching rules */ |
| /* AN_REQ_FLT_START_BE: 0x00000040 */ |
| #define AN_REQ_INSPECT_BE 0x00000080 /* inspect request contents in the backend */ |
| #define AN_REQ_HTTP_PROCESS_BE 0x00000100 /* process the backend's HTTP part */ |
| #define AN_REQ_HTTP_TARPIT 0x00000200 /* wait for end of HTTP tarpit */ |
| #define AN_REQ_SRV_RULES 0x00000400 /* use-server rules */ |
| #define AN_REQ_HTTP_INNER 0x00000800 /* inner processing of HTTP request */ |
| #define AN_REQ_PRST_RDP_COOKIE 0x00001000 /* persistence on rdp cookie */ |
| #define AN_REQ_STICKING_RULES 0x00002000 /* table persistence matching */ |
| /* AN_REQ_FLT_HTTP_HDRS: 0x00004000 */ |
| #define AN_REQ_HTTP_XFER_BODY 0x00008000 /* forward request body */ |
| #define AN_REQ_WAIT_CLI 0x00010000 |
| /* AN_REQ_FLT_XFER_DATA: 0x00020000 */ |
| /* AN_REQ_FLT_END: 0x00040000 */ |
| #define AN_REQ_ALL 0x0001bfbe /* all of the request analysers */ |
| |
| /* response analysers */ |
| /* AN_RES_FLT_START_FE: 0x00080000 */ |
| /* AN_RES_FLT_START_BE: 0x00100000 */ |
| #define AN_RES_INSPECT 0x00200000 /* content inspection */ |
| #define AN_RES_WAIT_HTTP 0x00400000 /* wait for HTTP response */ |
| #define AN_RES_STORE_RULES 0x00800000 /* table persistence matching */ |
| #define AN_RES_HTTP_PROCESS_BE 0x01000000 /* process backend's HTTP part */ |
| #define AN_RES_HTTP_PROCESS_FE 0x01000000 /* process frontend's HTTP part (same for now) */ |
| /* AN_RES_FLT_HTTP_HDRS: 0x02000000 */ |
| #define AN_RES_HTTP_XFER_BODY 0x04000000 /* forward response body */ |
| #define AN_RES_WAIT_CLI 0x08000000 |
| /* AN_RES_FLT_XFER_DATA: 0x10000000 */ |
| /* AN_RES_FLT_END: 0x20000000 */ |
| #define AN_RES_ALL 0x0de00000 /* all of the response analysers */ |
| |
| /* filters interleaved with analysers, see above */ |
| #define AN_REQ_FLT_START_FE 0x00000001 |
| #define AN_REQ_FLT_START_BE 0x00000040 |
| #define AN_REQ_FLT_HTTP_HDRS 0x00004000 |
| #define AN_REQ_FLT_XFER_DATA 0x00020000 |
| #define AN_REQ_FLT_END 0x00040000 |
| |
| #define AN_RES_FLT_START_FE 0x00080000 |
| #define AN_RES_FLT_START_BE 0x00100000 |
| #define AN_RES_FLT_HTTP_HDRS 0x02000000 |
| #define AN_RES_FLT_XFER_DATA 0x10000000 |
| #define AN_RES_FLT_END 0x20000000 |
| |
| /* Magic value to forward infinite size (TCP, ...), used with ->to_forward */ |
| #define CHN_INFINITE_FORWARD MAX_RANGE(unsigned int) |
| |
| |
| struct channel { |
| unsigned int flags; /* CF_* */ |
| unsigned int analysers; /* bit field indicating what to do on the channel */ |
| struct buffer buf; /* buffer attached to the channel, always present but may move */ |
| struct pipe *pipe; /* non-NULL only when data present */ |
| size_t output; /* part of buffer which is to be forwarded */ |
| unsigned int to_forward; /* number of bytes to forward after out without a wake-up */ |
| unsigned short last_read; /* 16 lower bits of last read date (max pause=65s) */ |
| unsigned char xfer_large; /* number of consecutive large xfers */ |
| unsigned char xfer_small; /* number of consecutive small xfers */ |
| unsigned long long total; /* total data read */ |
| int rex; /* expiration date for a read, in ticks */ |
| int wex; /* expiration date for a write or connect, in ticks */ |
| int rto; /* read timeout, in ticks */ |
| int wto; /* write timeout, in ticks */ |
| int analyse_exp; /* expiration date for current analysers (if set) */ |
| }; |
| |
| |
| /* Note about the channel structure |
| |
| A channel stores information needed to reliably transport data in a single |
| direction. It stores status flags, timeouts, counters, subscribed analysers, |
| pointers to a data producer and to a data consumer, and information about |
| the amount of data which is allowed to flow directly from the producer to |
| the consumer without waking up the analysers. |
| |
| A channel may buffer data into two locations : |
| - a visible buffer (->buf) |
| - an invisible buffer which right now consists in a pipe making use of |
| kernel buffers that cannot be tampered with. |
| |
| Data stored into the first location may be analysed and altered by analysers |
| while data stored in pipes is only aimed at being transported from one |
| network socket to another one without being subject to memory copies. This |
| buffer may only be used when both the socket layer and the data layer of the |
| producer and the consumer support it, which typically is the case with Linux |
| splicing over sockets, and when there are enough data to be transported |
| without being analyzed (transport of TCP/HTTP payload or tunnelled data, |
| which is indicated by ->to_forward). |
| |
| In order not to mix data streams, the producer may only feed the invisible |
| data with data to forward, and only when the visible buffer is empty. The |
| producer may not always be able to feed the invisible buffer due to platform |
| limitations (lack of kernel support). |
| |
| Conversely, the consumer must always take data from the invisible data first |
| before ever considering visible data. There is no limit to the size of data |
| to consume from the invisible buffer, as platform-specific implementations |
| will rarely leave enough control on this. So any byte fed into the invisible |
| buffer is expected to reach the destination file descriptor, by any means. |
| However, it's the consumer's responsibility to ensure that the invisible |
| data has been entirely consumed before consuming visible data. This must be |
| reflected by ->pipe->data. This is very important as this and only this can |
| ensure strict ordering of data between buffers. |
| |
| The producer is responsible for decreasing ->to_forward. The ->to_forward |
| parameter indicates how many bytes may be fed into either data buffer |
| without waking the parent up. The special value CHN_INFINITE_FORWARD is |
| never decreased nor increased. |
| |
| The buf->o parameter says how many bytes may be consumed from the visible |
| buffer. This parameter is updated by any buffer_write() as well as any data |
| forwarded through the visible buffer. Since the ->to_forward attribute |
| applies to data after buf->p, an analyser will not see a buffer which has a |
| non-null ->to_forward with buf->i > 0. A producer is responsible for raising |
| buf->o by min(to_forward, buf->i) when it injects data into the buffer. |
| |
| The consumer is responsible for decreasing ->buf->o when it sends data |
| from the visible buffer, and ->pipe->data when it sends data from the |
| invisible buffer. |
| |
| A real-world example consists in part in an HTTP response waiting in a |
| buffer to be forwarded. We know the header length (300) and the amount of |
| data to forward (content-length=9000). The buffer already contains 1000 |
| bytes of data after the 300 bytes of headers. Thus the caller will set |
| buf->o to 300 indicating that it explicitly wants to send those data, and |
| set ->to_forward to 9000 (content-length). This value must be normalised |
| immediately after updating ->to_forward : since there are already 1300 bytes |
| in the buffer, 300 of which are already counted in buf->o, and that size |
| is smaller than ->to_forward, we must update buf->o to 1300 to flush the |
| whole buffer, and reduce ->to_forward to 8000. After that, the producer may |
| try to feed the additional data through the invisible buffer using a |
| platform-specific method such as splice(). |
| |
| The ->to_forward entry is also used to detect whether we can fill the buffer |
| or not. The idea is that we need to save some space for data manipulation |
| (mainly header rewriting in HTTP) so we don't want to have a full buffer on |
| input before processing a request or response. Thus, we ensure that there is |
| always global.maxrewrite bytes of free space. Since we don't want to forward |
| chunks without filling the buffer, we rely on ->to_forward. When ->to_forward |
| is null, we may have some processing to do so we don't want to fill the |
| buffer. When ->to_forward is non-null, we know we don't care for at least as |
| many bytes. In the end, we know that each of the ->to_forward bytes will |
| eventually leave the buffer. So as long as ->to_forward is larger than |
| global.maxrewrite, we can fill the buffer. If ->to_forward is smaller than |
| global.maxrewrite, then we don't want to fill the buffer with more than |
| buf->size - global.maxrewrite + ->to_forward. |
| |
| A buffer may contain up to 5 areas : |
| - the data waiting to be sent. These data are located between buf->p-o and |
| buf->p ; |
| - the data to process and possibly transform. These data start at |
| buf->p and may be up to ->i bytes long. |
| - the data to preserve. They start at ->p and stop at ->p+i. The limit |
| between the two solely depends on the protocol being analysed. |
| - the spare area : it is the remainder of the buffer, which can be used to |
| store new incoming data. It starts at ->p+i and is up to ->size-i-o long. |
| It may be limited by global.maxrewrite. |
| - the reserved area : this is the area which must not be filled and is |
| reserved for possible rewrites ; it is up to global.maxrewrite bytes |
| long. |
| */ |
| |
| #endif /* _HAPROXY_CHANNEL_T_H */ |
| |
| /* |
| * Local variables: |
| * c-indent-level: 8 |
| * c-basic-offset: 8 |
| * End: |
| */ |