more examples of b[] syntax, fix func arg passing

Add getitem api to BPF object to reference tables

To simplify some common usage patterns, add a getitem api to the BPF
class. This wraps the get_table() api and allows the api user to skip
keeping their own get_table handle.

Fixes: #137
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Change API of attach_kprobe to take a name argument

Per feedback on the attach_kprobe api, change up the arguments to remove
the load_func that typically preceeds the call. Instead, move this
inside the attach_kprobe implementation. Also, this makes attach_kprobe
need to be non-static. The same applies to attach_kretprobe.

Old:
fn = b.load_func("hello", BPF.KPROBE)
BPF.attach_kprobe(fn, "sys_clone")

New:
b.attach_kprobe(event="sys_clone", fn_name="hello")

Note that the kwarg style is not required, but I fixed up the current
usages to provide readability.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

some bcc examples and tools

Add format string argument to bpf-run

Usage:
bpf-run -f "time={3} output={5}"
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Add bpf-run command line tool

Example usage:
sudo bpf-run -p sys_clone -c 'bpf_trace_printk("Hello, World!\n");' -t
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

add dhcp support for tunnel-mesh

Signed-off-by: Yonghong Song <yhs@plumgrid.com>

add vlan_learning and distributed_bridge in libbcc package

distributed_bridge: check ip address before validating traffic

Signed-off-by: Wei-Chun Chao <weichunc@plumgrid.com>

Signed-off-by: Yonghong Song <yhs@plumgrid.com>

distributed_bridge: wait for ns comes up before validating traffic

Sometimes it takes longer for ns to complete configuration.
Signed-off-by: Wei-Chun Chao <weichunc@plumgrid.com>

test_brb2: only account for IP and ARP packets

Changes to support map entry read/write in fuse

Sometimes background noise fails the test
Signed-off-by: Wei-Chun Chao <weichunc@plumgrid.com>

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Expose an individual API of the what is done in table_update, that lets
the caller use the module to parse keys for it.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

clean up potential conflict veth before creating new one in create_ns

Signed-off-by: Yonghong Song <yhs@plumgrid.com>

Signed-off-by: Yonghong Song <yhs@plumgrid.com>

Add printf for key/leaf and fix trace_printk bug

There was an issue where the rewrite of bpf_trace_printk combined with
conversion of function argument to ctx->$reg was mangling the text. Fix
up this case and add a test.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

This extends upon the sscanf reader functionality, with the intent of
providing key/leaf pretty printing
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Fix recursive loop in parsing pointer to self struct

Issue occurs in the description visitor class, when the struct used in a
map key is a pointer to self, as in:

struct node;
struct node {
  struct node *next;
};

Avoid this in the desc by using "unsigned long long" for all pointers.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Signed-off-by: Yonghong Song <yhs@plumgrid.com>