tracing01-xdp-simple: README.org add org-mode syntax highlighting

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>

Author: netoptimizer

tracing01-xdp-simple/README.org

@@ -11,18 +11,17 @@ stats application.
   - [[#tracepoint-program-section][Tracepoint program section]]
   - [[#tracepoint-arguments][Tracepoint arguments]]
   - [[#tracepoint-attaching][Tracepoint attaching]]
-  - [[#hash-map][HASH map]]
+- [[#hash-map][HASH map]]
 - [[#assignments][Assignments]]
   - [[#assignment-1-setting-up-your-test-lab][Assignment 1: Setting up your test lab]]
   - [[#assignment-2-load-tracepoint-monitor-program][Assignment 2: Load tracepoint monitor program]]
 
-
 * XDP tracepoints
 
 The eBPF programs can be attached also to tracepoints. There are
 several tracepoints related to the xdp tracepoint subsystem:
 
-#+begin_example sh
+#+begin_src sh
 ls /sys/kernel/debug/tracing/events/xdp/
 xdp_cpumap_enqueue
 xdp_cpumap_kthread
@@ -32,24 +31,24 @@ xdp_redirect
 xdp_redirect_err
 xdp_redirect_map
 xdp_redirect_map_err
-#+end_example
+#+end_src
 
 ** Tracepoint program section
 
 The bpf library expects the tracepoint eBPF program to be stored
 in a section with following name:
 
-#+begin_example sh
+#+begin_src C
 tracepoint/<sys>/<tracepoint>
-#+end_example
+#+end_src
 
 where =<sys>= is the tracepoint subsystem and =<tracepoint>= is
 the tracepoint name, which can be done with following construct:
 
-#+begin_example sh
+#+begin_src sh
 SEC("tracepoint/xdp/xdp_exception")
 int trace_xdp_exception(struct xdp_exception_ctx *ctx)
-#+end_example
+#+end_src
 
 ** Tracepoint arguments
 
@@ -58,7 +57,7 @@ to the structure, that defines the tracepoint fields.
 
 Like for xdp:xdp_exception tracepoint:
 
-#+begin_example sh
+#+begin_src C
 struct xdp_exception_ctx {
         __u64 __pad;      // First 8 bytes are not accessible by bpf code
         __s32 prog_id;    //      offset:8;  size:4; signed:1;
@@ -67,11 +66,11 @@ struct xdp_exception_ctx {
 };
 
 int trace_xdp_exception(struct xdp_exception_ctx *ctx)
-#+end_example
+#+end_src
 
 This struct is exported in tracepoint format file:
 
-#+begin_example sh
+#+begin_src C
 # cat /sys/kernel/debug/tracing/events/xdp/xdp_exception/format
 ...
         field:unsigned short common_type;       offset:0;       size:2; signed:0;
@@ -83,16 +82,16 @@ This struct is exported in tracepoint format file:
         field:u32 act;  offset:12;      size:4; signed:0;
         field:int ifindex;      offset:16;      size:4; signed:1;
 ...
-#+end_example
+#+end_src
 
 ** Tracepoint attaching
 
 To load a tracepoint program for this example we use following bpf
 library helper function:
 
-#+begin_example sh
+#+begin_src sh
 bpf_prog_load(cfg->filename, BPF_PROG_TYPE_TRACEPOINT, &obj, &bpf_fd))
-#+end_example
+#+end_src
 
 It loads all the programs from the object together with maps and
 returns file descriptor of the first one.
@@ -101,9 +100,9 @@ To attach the program to the tracepoint we need to create a tracepoint
 perf event and attach the eBPF program to it, using its file descriptor
 via PERF_EVENT_IOC_SET_BPF ioctl call:
 
-#+begin_example sh
+#+begin_src sh
 err = ioctl(fd, PERF_EVENT_IOC_SET_BPF, bpf_fd);
-#+end_example
+#+end_src
 
 Please check trace_load_and_stats.c load_bpf_and_trace_attach function
 for all the details.
@@ -112,19 +111,19 @@ for all the details.
 
 This example is using PERCPU HASH map, that stores number of aborted
 packets for interface
-#+begin_example sh
+#+begin_src C
 struct bpf_map_def SEC("maps") xdp_stats_map = {
         .type        = BPF_MAP_TYPE_PERCPU_HASH,
         .key_size    = sizeof(__s32),
         .value_size  = sizeof(__u64),
         .max_entries = 10,
 };
-#+end_example
+#+end_src
 
 The interface is similar to the ARRAY map except that we need to specifically
 create new element in the hash if it does not exist:
 
-#+begin_example sh
+#+begin_src C
 /* Lookup in kernel BPF-side returns pointer to actual data. */
 valp = bpf_map_lookup_elem(&xdp_stats_map, &key);
 
@@ -137,7 +136,7 @@ if (!valp) {
 }
 
 (*valp)++;
-#+end_example
+#+end_src
 
 Please check trace_prog_kern.c for the full code.
 
@@ -151,44 +150,44 @@ Basic02 - loading a program by name [[https://github.com/xdp-project/xdp-tutoria
 and load XDP program from xdp_prog_kern.o that will abort every
 incoming packet:
 
-#+begin_example sh
+#+begin_src C
 SEC("xdp_abort")
 int xdp_drop_func(struct xdp_md *ctx)
 {
         return XDP_ABORTED;
 }
-#+end_example
+#+end_src
 
 with xdp_loader from previous lessson:
 Assignment 2: Add xdp_abort program [[https://github.com/xdp-project/xdp-tutorial/tree/master/basic02-prog-by-name#assignment-2-add-xdp_abort-program]]
 
 Setup the environment:
 
-#+begin_example sh
+#+begin_src sh
 $ sudo ../testenv/testenv.sh setup --name veth-basic02
-#+end_example
+#+end_src
 
 Load the XDP program, tak produces aborted packets:
 
-#+begin_example sh
+#+begin_src sh
 $ sudo ./xdp_loader --dev veth-basic02 --force --progsec xdp_abort
-#+end_example
+#+end_src
 
 and make some packets:
 
-#+begin_example sh
+#+begin_src sh
 $ sudo ../testenv/testenv.sh enter --name veth-basic02
 # ping  fc00:dead:cafe:1::1
 PING fc00:dead:cafe:1::1(fc00:dead:cafe:1::1) 56 data bytes
-#+end_example
+#+end_src
 
 ** Assignment 2: Load tracepoint monitor program
 
 Now when you run the trace_load_and_stats application it will
 load and attach the tracepoint eBPF program and display number
 of aborted packets per interface:
 
-#+begin_example
+#+begin_src sh
 # ./trace_load_and_stats
 Success: Loaded BPF-object(trace_prog_kern.o)
 
@@ -199,4 +198,4 @@ veth-basic02 (2)
 veth-basic02 (4)
 veth-basic02 (6)
 ...
-#+end_example
+#+end_src