Add ip_get_proto()

src/common-static.h

@@ -43,6 +43,7 @@ static inline size_t str_cpy (char *restrict dst, const char *restrict src, size
     return i;
 }
 
+_pure_
 static inline int str_cmp (const char *restrict sa, const char *restrict sb)
 {
     if (!sa || !sb)
@@ -55,6 +56,7 @@ static inline int str_cmp (const char *restrict sa, const char *restrict sb)
     return 1;
 }
 
+_pure_
 static inline size_t str_len (const char *restrict str)
 {
     if (!str)
@@ -111,16 +113,19 @@ static inline void buffer_format (buffer_t *buffer)
     buffer->read  = buffer->data;
 }
 
+_pure_
 static inline size_t buffer_size (buffer_t *buffer)
 {
     return buffer->end-buffer->data;
 }
 
+_pure_
 static inline size_t buffer_write_size (buffer_t *buffer)
 {
     return buffer->end-buffer->write;
 }
 
+_pure_
 static inline size_t buffer_read_size (buffer_t *buffer)
 {
     return buffer->write-buffer->read;

src/common.h

@@ -20,6 +20,8 @@
 #define _printf_(A,B)  __attribute__((format(printf,A,B)))
 #define _noreturn_     __attribute__((noreturn))
 #define _unused_       __attribute__((unused))
+#define _pure_         __attribute__((pure))
+#define _const_        __attribute__((const))
 #define _align_(...)   __attribute__((aligned(__VA_ARGS__)))
 
 typedef struct buffer buffer_t;

src/ip-static.h

@@ -2,6 +2,7 @@
 
 #include <stdint.h>
 
+_pure_
 static inline int ip_get_version (const uint8_t *data, size_t size)
 {
     if (size<20)   // XXX
@@ -10,6 +11,7 @@ static inline int ip_get_version (const uint8_t *data, size_t size)
     return data[0]>>4;
 }
 
+_pure_
 static inline ssize_t ip_get_size (const uint8_t *data, size_t size)
 {
     switch (ip_get_version(data, size)) {
@@ -23,3 +25,18 @@ static inline ssize_t ip_get_size (const uint8_t *data, size_t size)
 
     return 0;
 }
+
+_pure_
+static inline ssize_t ip_get_proto (const uint8_t *data, size_t size)
+{
+    switch (ip_get_version(data, size)) {
+    case 4:
+        return data[9];
+    case 6:
+        return data[6];
+    case -1:
+        return -1;
+    }
+
+    return 0;
+}