diff options
Diffstat (limited to 'test/packetdrill/tcp_options.h')
| -rw-r--r-- | test/packetdrill/tcp_options.h | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/test/packetdrill/tcp_options.h b/test/packetdrill/tcp_options.h new file mode 100644 index 0000000..4967c2d --- /dev/null +++ b/test/packetdrill/tcp_options.h @@ -0,0 +1,129 @@ +/* + * Copyright 2013 Google Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ +/* + * Author: ncardwell@google.com (Neal Cardwell) + * + * Interfaces for reading and writing TCP options in their wire format. + */ + +#ifndef __TCP_OPTIONS_H__ +#define __TCP_OPTIONS_H__ + +#include "types.h" + +#include "packet.h" + +#define MAX_TCP_OPTION_BYTES (MAX_TCP_HEADER_BYTES - (int)sizeof(struct tcp)) + +/* TCP Fast Open uses the following magic number to be after the + * option value for sharing TCP experimental options. + * + * For a description of experimental options, see: + * http://tools.ietf.org/html/draft-ietf-tcpm-experimental-options-00 + * + * For a description of TFO, see: + * http://tools.ietf.org/html/draft-cheng-tcpm-fastopen-02 + */ +#define TCPOPT_FASTOPEN_MAGIC 0xF989 + +/* Experimental TFO option must have: + * 1-byte kind, 1-byte length, and 2-byte magic: */ +#define TCPOLEN_EXP_FASTOPEN_BASE 4 /* smallest legal TFO option size */ + +/* RFC7413 TFO option must have: 1-byte kind, 1-byte length: */ +#define TCPOLEN_FASTOPEN_BASE 2 /* smallest legal TFO option size */ + +/* The TFO option base prefix leaves this amount of space: */ +#define MAX_TCP_FAST_OPEN_COOKIE_BYTES \ + (MAX_TCP_OPTION_BYTES - TCPOLEN_FASTOPEN_BASE) +#define MAX_TCP_FAST_OPEN_EXP_COOKIE_BYTES \ + (MAX_TCP_OPTION_BYTES - TCPOLEN_EXP_FASTOPEN_BASE) + +/* Represents a list of TCP options in their wire format. */ +struct tcp_options { + u8 data[MAX_TCP_OPTION_BYTES]; /* The options data, in wire format */ + u8 length; /* The length, in bytes, of the data */ +}; + +/* Specification of a TCP SACK block (RFC 2018) */ +struct sack_block { + u32 left; /* left edge: 1st sequence number in block */ + u32 right; /* right edge: 1st sequence number just past block */ +}; + +/* Represents a single TCP option in its wire format. Note that for + * EOL and NOP options the length and data field are not included in + * the on-the-wire data. For other options, the length field describes + * the number of bytes of the struct that go on the wire. */ +struct tcp_option { + u8 kind; + u8 length; /* bytes on the wire; includes kind and length byte */ + union { + struct { + u16 bytes; /* in network order */ + } mss; + struct { + u32 val; /* in network order */ + u32 ecr; /* in network order */ + } time_stamp; + struct { + u8 shift_count; + } window_scale; + struct { + /* actual number of blocks will be 1..4 */ + struct sack_block block[4]; + } sack; + struct { + u8 digest[TCP_MD5_DIGEST_LEN]; + } md5; /* TCP MD5 Signature Option: RFC 2385 */ + struct { + /* The fast open chookie should be 4-16 bytes + * of cookie, multiple of 2 bytes, but we + * allow for larger sizes, so we can test what + * stacks do with illegal options. + */ + u8 cookie[MAX_TCP_FAST_OPEN_COOKIE_BYTES]; + } fast_open; + struct { + u16 magic; /* must be TCPOPT_FASTOPEN_MAGIC */ + u8 cookie[MAX_TCP_FAST_OPEN_EXP_COOKIE_BYTES]; + } fast_open_exp; + } data; +} __packed tcp_option; + +/* Allocate a new options list. */ +extern struct tcp_options *tcp_options_new(void); + +/* Allocate a new option and initialize its kind and length fields. */ +extern struct tcp_option *tcp_option_new(u8 kind, u8 length); + +/* Appends the given option to the given list of options. Returns + * STATUS_OK on success; on failure returns STATUS_ERR and sets + * error message. + */ +extern int tcp_options_append(struct tcp_options *options, + struct tcp_option *option); + +/* Calculate the number of SACK blocks in a SACK option of the given + * length and store it in *num_blocks. Returns STATUS_OK on success; + * on failure returns STATUS_ERR and sets error message. + */ +extern int num_sack_blocks(u8 opt_len, int *num_blocks, char **error); + +#endif /* __TCP_OPTIONS_H__ */ |