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Implement incrementing of proto field at runtime with min & max
parameters, by default if the 'min' parameter is not specified then
original value is used. For fields which len is greater than 4 - last 4
bytes are incremented as 4 byte value (this trick is used to increment
MAC/IPv6 addresses).
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add basic infrastructure for update proto field value at runtime by
dynamic field function.
Extended 'struct packet_dyn' with proto fields which has dynamically
changing values at runtime.
Added 'field_changed' callback for proto header which may be used for
check if csum updating is needed. This callback is called after field
was changed at runtime.
Added 'packet_update' callback to let proto header know when to apply
final proto header changes at runtime (e.g. - csum update).
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Currently struct proto_hdr is used twofold:
1) Statically define protocol behavior, i.e. all the *_hdr definitions in
trafgen_l{2,3,4}.c which map a protocol id/layer to a set of callback
functions.
2) For each packet created at parse time the struct is memcpy()'ed
(including all the static information from 1) and then used to store
dynamic information at parse/run time.
Thus, struct proto_hdr members such as the proto id, layer and the
pointers callback functions get copied for each created packet (in
addition to the other fields which get changed during parsing). Also,
static/dynamic information get mixed and we e.g. can't make the protocol
definitions const to ensure they'll not get changed by mistake.
Rather than copying the struct proto_hdr for every packet, clearly
separate the two purposes defined above by splitting struct proto_hdr
into two structs:
1) struct proto_ops for the static (const) protocol behavior definition
2) struct proto_hdr (reduced) for dynamic information
struct proto_hdr keeps a pointer to the corresponding proto_ops instance
and uses it to execute the corresponding callbacks.
Reference: https://groups.google.com/forum/#!msg/netsniff-ng/20RvwJdh50Y/eMkbmKSaBgAJ
Acked-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Make the __proto_field_set_bytes() take a const uint8_t *bytes pointer
and also changed all callers accordingly.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Protocols are registered early at startup and aren't changed at runtime.
In order to speed up lookup while parsing, store the pointers to the
protocol definitions (struct proto_hdr) in an array, indexed by protocol
id rather than in a linked list.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Use a module variable to access the proto context instead of storing a
pointer in every header.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Usually proto fields array are sorted in the same order as the
respective enum. Thus, the id can be used used as an array index for
faster lookup.
Add an explanatory comment and enforce the correspondence of id and
index using bug_on().
This will make csum field calculation a little faster at runtime.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Until now headers were used only for packet creation at compile time,
which does not allow to handle dynamic field updates at runtime. To
support dynamic updates, it is necessary to keep the proto_hdr entries
around after packet compilation so we can reference the header fields to
dynamically update.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
[tk: Adjust patch description, simplify code]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Using of current_packet() is not possible for dynamically updated fields
so we need to keep the packet index in proto_hdr struct to reference the
correct packet.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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It is potentially dangerous to use the user specified IHL field for
csum calculation, as it might lead to read buffer overflows.
Instead introduce and use the len field in struct proto_hdr which is
calculated automatically after the header is built.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
[tk: reword commit message]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Support for generating simple IPv6 headers using the 'ip6()/ipv6()'
trafgen generation function.
Fields supported:
ver|version Version (default: 6)
tc|tclass Traffic class (default: 0)
fl|flow Flow Label (default: 0)
len|length Payload length (calculated by default)
nh|nexthdr Type of next header (default: 0)
hl|hoplimit|ttl Hop Limit, TTL (default: 0)
sa|saddr Source IPv6 address (default: device address)
da|daddr Destination IPv6 address (default: 0:0:0:0:0:0:0:0)
Examples:
{ eth(), ipv6(daddr=1:2:3:4:5:6:7:8) }
{ ipv6(tc=2, hl=3, daddr=::1) }
{ eth(), ipv6(nh=58, sa=2001:db8::, da=::1), 128, 0, 0x52, 0x03, 0, 0, 0, 0 }
If not explicitely specified, the lower header is initialized as Ethernet.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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In some cases we use panic() in situations where the error could only
happen due to an implementation error. Use bug() there as it is more
applicable, as panic() is mainly used to report system call errors.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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proto_lower_header() is the only caller for proto_current_header() which
already checks header_count > 0, so inline proto_current_header() and
omit the additional check and a panic() which thus can never be
triggered.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Current logic does OR of existing field value & shift-masked
specified value, which is not enough as 0s bits from
the specified value will be not set (be cause of OR),
so fixed it by reseting original field value by AND with
reverted field mask, in otherwords - bits part of original field
value is reset to 0s and only after OR-ed with specified shift-masked
value.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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After commit 88b359d2aa7e ("trafgen: proto: Simplify getting lower
protocol after init") proto_current_header() is no longer used outside
trafgen_proto.c, so make it static.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add set_next_proto callback to proto_hdr struct to allow lower
protocol set next protocol id by enum proto_id.
Extended proto_lower_default_add(...) function to take upper protocol
to delegate it's id to lower protocol to set next protocol field.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Change proto_header_init(...) and proto_lower_default_add(...)
functions to return struct proto_hdr * to do not call
proto_current_header(...) after, so it makes more sense to get struct
proto_hdr * right after initializing protocol by id.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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It's not changed inside the function, so mark it as const. Also adjust
the header guards.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add trafgen_l4.c module with generation UDP header fields.
UDP protocol generation logic automaticaly sets the protocol field of
the lower level protocol to IPPROTO_UDP by default (if it is IPv4).
Also checksum & length are calculated and set if it is not given by the
user.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add L3 module for implement L3 layer protocols generation.
Implemented setting of IPv4 header with all fields except options.
By default IPv4 address of output device is used as src ip address.
On finish (after packet is specified) - total len & checksum are calculated.
Meanwhile Ethernet protocol is initialized as default lower header.
If the lower protocol is IPv4 then IPv4 protocol id is set
to IP-in-IP in lower protocol header.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add helper which fills a device's ipv4 addr to the specified protocol field.
It will be used by protocols like ARP, IPv4, etc.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add trafgen_l2.c module for generating L2 related headers.
Add Ethernet header generating. By default source MAC address
is used from the specified output device.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add helper function to set device's MAC address to protocol field which may
be used by Ethernet & ARP protocol header generation functions.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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Add new trafgen_proto.c module with basic protocol header fields
generation logic. This will allow to support protocol specific keywords
in the trafgen configuration language.
Each protocol must implement struct proto_hdr and register it to the
global proto list.
Protocol headers consist of a set of fields, and each field must be
described via struct proto_field by specifying unique id, length and
offset (relative to the header start). Fields smaller than 8 bits can be
described via left shift & mask.
The following callbacks are invoked to perform special actions to build
the header during parsing:
1) header_init - required fields must be added to the packet and
initialized with default values.
2) header_finish - it is invoked when header is specified, all user
specified fields are set.
3) packet_finish - callback is invoked from upper to lower header
to calculate fields depending on upper layers such as total
length or checksum.
The protocol generation API provides convenience protocol field
setters/getters to to be used in the parser while crafting the packet.
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
[tk: wordsmithing on commit message, minor variable type changes]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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