ngx_strnstr()
diff --git a/src/core/ngx_string.h b/src/core/ngx_string.h
index e17fc13..3199384 100644
--- a/src/core/ngx_string.h
+++ b/src/core/ngx_string.h
@@ -126,6 +126,8 @@
 ngx_int_t ngx_strcasecmp(u_char *s1, u_char *s2);
 ngx_int_t ngx_strncasecmp(u_char *s1, u_char *s2, size_t n);
 
+u_char *ngx_strnstr(u_char *s1, char *s2, size_t n);
+
 u_char *ngx_strstrn(u_char *s1, char *s2, size_t n);
 u_char *ngx_strcasestrn(u_char *s1, char *s2, size_t n);