bpfc: allow bpf programs to be passed to cpp

This patch allows bpf programs to be passed to the C preprocessor
before handing over to bpfc. Example:

  #define ETH_P_IP        0x800

  ldh [12]
  jne #ETH_P_IP, drop
  ldb [23]
  jneq #6, drop
  ldh [20]
  jset #0x1fff, drop
  ldxb 4 * ([14] & 0xf)
  ldh [x + 14]
  jeq #0x16, pass
  ldh [x + 16]
  jne #0x16, drop
  pass: ret #-1
  drop: ret #0

Compile with: bpfc -i foo -p

Suggested-by: John Lange <JLange@trendium.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/bpf_lexer.l b/bpf_lexer.l
index a2ff90a..185faae 100644
--- a/bpf_lexer.l
+++ b/bpf_lexer.l
@@ -119,6 +119,7 @@ label		[a-zA-Z_][a-zA-Z0-9_]+
 
 "/*"([^\*]|\*[^/])*"*/" { /* NOP */ }
 ";"[^\n]*	{/* NOP */}
+^#.*		{/* NOP */}
 "\n"		{ yylineno++; }
 [ \t]+		{/* NOP */ }
 .		{ printf("Unknown character '%s'", yytext);