diff options
Diffstat (limited to 'share/man/man4/bpf.4')
| -rw-r--r-- | share/man/man4/bpf.4 | 54 |
1 files changed, 27 insertions, 27 deletions
diff --git a/share/man/man4/bpf.4 b/share/man/man4/bpf.4 index f1b1311..58eb6be 100644 --- a/share/man/man4/bpf.4 +++ b/share/man/man4/bpf.4 @@ -605,6 +605,11 @@ array initializers: .Fn BPF_STMT opcode operand and .Fn BPF_JUMP opcode operand true_offset false_offset . +.Sh FILES +.Bl -tag -compact -width /dev/bpfXXX +.It Pa /dev/bpf Ns Sy n +the packet filter device +.El .Sh EXAMPLES The following filter is taken from the Reverse ARP Daemon. It accepts only Reverse ARP requests. @@ -673,33 +678,6 @@ struct bpf_insn insns[] = { .%A Jacobson V. .%T "An efficient, extensible, and portable network monitor" .Re -.Sh FILES -.Bl -tag -compact -width /dev/bpfXXX -.It Pa /dev/bpf Ns Sy n -the packet filter device -.El -.Sh BUGS -The read buffer must be of a fixed size (returned by the -.Dv BIOCGBLEN -ioctl). -.Pp -A file that does not request promiscuous mode may receive promiscuously -received packets as a side effect of another file requesting this -mode on the same hardware interface. -This could be fixed in the kernel with additional processing overhead. -However, we favor the model where -all files must assume that the interface is promiscuous, and if -so desired, must utilize a filter to reject foreign packets. -.Pp -Data link protocols with variable length headers are not currently supported. -.Pp -The -.Dv SEESENT -flag has been observed to work incorrectly on some interface -types, including those with hardware loopback rather than software loopback, -and point-to-point interfaces. -It appears to function correctly on a -broad range of Ethernet-style interfaces. .Sh HISTORY The Enet packet filter was created in 1980 by Mike Accetta and Rick Rashid at Carnegie-Mellon University. @@ -724,3 +702,25 @@ of Lawrence Berkeley Laboratory, implemented BPF in Summer 1990. Much of the design is due to .An Van Jacobson . +.Sh BUGS +The read buffer must be of a fixed size (returned by the +.Dv BIOCGBLEN +ioctl). +.Pp +A file that does not request promiscuous mode may receive promiscuously +received packets as a side effect of another file requesting this +mode on the same hardware interface. +This could be fixed in the kernel with additional processing overhead. +However, we favor the model where +all files must assume that the interface is promiscuous, and if +so desired, must utilize a filter to reject foreign packets. +.Pp +Data link protocols with variable length headers are not currently supported. +.Pp +The +.Dv SEESENT +flag has been observed to work incorrectly on some interface +types, including those with hardware loopback rather than software loopback, +and point-to-point interfaces. +It appears to function correctly on a +broad range of Ethernet-style interfaces. |
