The pcap library emits classic BPF (32 bit) and is useful for
creating filter programs.  The DPDK BPF library only implements
extended BPF (eBPF).  Add an function to convert from old to
new.

The rte_bpf_convert function uses rte_malloc to put the resulting
program in hugepage shared memory so it can be passed from a
secondary process to a primary process.

The code to convert was originally done as part of the Linux
kernel implementation then converted to a userspace program.
Both authors have agreed that it is allowable to license this
as BSD licensed in DPDK.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/bpf/bpf_convert.c | 570 ++++++++++++++++++++++++++++++++++++++++++
 lib/bpf/meson.build   |   5 +
 lib/bpf/rte_bpf.h     |  25 ++
 lib/bpf/version.map   |   6 +
 4 files changed, 606 insertions(+)
 create mode 100644 lib/bpf/bpf_convert.c

diff --git a/lib/bpf/meson.build b/lib/bpf/meson.build
index 63cbd60185e0..54f7610ae990 100644
--- a/lib/bpf/meson.build
+++ b/lib/bpf/meson.build

@@ -25,3 +25,8 @@ if dep.found()
     sources += files('bpf_load_elf.c')
     ext_deps += dep
 endif
+
+if dpdk_conf.has('RTE_PORT_PCAP')

+    sources += files('bpf_convert.c')
+    ext_deps += pcap_dep
+endif

diff --git a/lib/bpf/rte_bpf.h b/lib/bpf/rte_bpf.h
index 69116f36ba8b..2f23e272a376 100644
--- a/lib/bpf/rte_bpf.h
+++ b/lib/bpf/rte_bpf.h

@@ -198,6 +198,31 @@ rte_bpf_exec_burst(const struct rte_bpf *bpf, void *ctx[], uint64_t rc[],
 int
 rte_bpf_get_jit(const struct rte_bpf *bpf, struct rte_bpf_jit *jit);

+#ifdef RTE_PORT_PCAP
+
+struct bpf_program;
+
+/**
+ * Convert a Classic BPF program from libpcap into a DPDK BPF code.
+ *
+ * @param prog
+ *  Classic BPF program from pcap_compile().
+ * @param prm
+ *  Result Extended BPF program.
+ * @return
+ *   Pointer to BPF program (allocated with *rte_malloc*)
+ *   that is used in future BPF operations,
+ *   or NULL on error, with error code set in rte_errno.
+ *   Possible rte_errno errors include:
+ *   - EINVAL - invalid parameter passed to function
+ *   - ENOMEM - can't reserve enough memory
+ */
+__rte_experimental
+struct rte_bpf_prm *
+rte_bpf_convert(const struct bpf_program *prog);
+
+#endif
+
 #ifdef __cplusplus
 }
 #endif

diff --git a/lib/bpf/version.map b/lib/bpf/version.map
index 0bf35f487666..47082d5003ef 100644
--- a/lib/bpf/version.map
+++ b/lib/bpf/version.map

@@ -14,3 +14,9 @@ DPDK_22 {

 	local: *;
 };
+
+EXPERIMENTAL {
+	global:
+
+	rte_bpf_convert;
+};
--