send 0x04 0x00 ns: 258 0x03
The device name can be omitted if only a single device exists in the system when the send command is executed.
The attributes set meta-data in the packet. The following attributes are supported:
|nfmark||0||the network filter mark value|
|(used by the fw classifier)|
|priority||0||priority value the ``real'' kernel derives from|
|the TOS byte or some socket options|
|protocol||ETH_P_IP||protocol number obtained from link layer|
|tc_index||0||shared traffic control decision|
Attributes can be set with two priorities: ``default'', which is indicated by the keyword default before the assignment, and ``normal'', which is indicated by the absence of that keyword. Setting an attribute with ``default'' priority doesn't change that attribute if it has previously been set with ``normal'' priority. In all other cases, the attribute is changed. Setting attributes with ``default'' priority is mainly used in macros, e.g. in IP_PCK and IP6_PCK.
All attributes have a global default value and the default priority ``default''. This can be changed with the attribute command described in section 6.2.2.
Note: the attributes nfmark, priority, and tc_index
are usually reset to their global default values when crossing links.6.3 They are preserved when invoking tcsim
with the -p option. (Use with caution: it's very easy to forget
skb->tc_index, and things will still appear to
work, because the value set at a previous host is re-used, which
would of course not happen in real life.)
Values are arithmetic or bit expressions, IPv4 addresses in dotted quad notation (e.g. 10.0.0.1), IPv6 addresses in any of the formats described in [RFC2373] or variables ($var). Numeric constants can be given as decimal, hexadecimal, or binary (0b) numbers. Also a Perl-like repetition operator x is available.
By default, values are treated as bytes (Exception: dotted quads are treated as four bytes in network byte order.) A value can optionally be prefixed by a type:
|b:||byte (8 bits)|
|ns:||network short (16 bits)|
|hs:||host short (16 bits)|
|nl:||network long (32 bits)|
|hl:||host long (32 bits)|
|ipv4:||IPv4 address (32 bits)|
|ipv6:||IPv6 address (128 bits)|
tcsim reports an error if a value is too large for the specified size.
ns: 258 is equivalent to
Note that, when using a variable containing a value larger than a byte, the type needs to be specified.