Re: [PATCH bpf-next v3] libbpf: fix compilation errors on ubuntu 16.04

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 7/12/21 12:26 PM, Daniel Borkmann wrote:
On 7/12/21 9:20 PM, Yonghong Song wrote:
libbpf is used as a submodule in bcc.
When importing latest libbpf repo in bcc, I observed the
following compilation errors when compiling on ubuntu 16.04.
   .../netlink.c:416:23: error: ‘TC_H_CLSACT’ undeclared (first use in this function)
      *parent = TC_H_MAKE(TC_H_CLSACT,
                          ^
   .../netlink.c:418:9: error: ‘TC_H_MIN_INGRESS’ undeclared (first use in this function)
            TC_H_MIN_INGRESS : TC_H_MIN_EGRESS);
            ^
   .../netlink.c:418:28: error: ‘TC_H_MIN_EGRESS’ undeclared (first use in this function)
            TC_H_MIN_INGRESS : TC_H_MIN_EGRESS);
                               ^
   .../netlink.c: In function ‘__get_tc_info’:
   .../netlink.c:522:11: error: ‘TCA_BPF_ID’ undeclared (first use in this function)
     if (!tbb[TCA_BPF_ID])
              ^

In ubuntu 16.04, TCA_BPF_* enumerator looks like below
   enum {
    TCA_BPF_UNSPEC,
    TCA_BPF_ACT,
    ...
    TCA_BPF_NAME,
    TCA_BPF_FLAGS,
    __TCA_BPF_MAX,
   };
   #define TCA_BPF_MAX    (__TCA_BPF_MAX - 1)
while in latest bpf-next, the enumerator looks like
   enum {
    TCA_BPF_UNSPEC,
    ...
    TCA_BPF_FLAGS,
    TCA_BPF_FLAGS_GEN,
    TCA_BPF_TAG,
    TCA_BPF_ID,
    __TCA_BPF_MAX,
   };

In this patch, TCA_BPF_ID is defined as a macro with proper value and this
works regardless of whether TCA_BPF_ID is defined in uapi header or not.
TCA_BPF_MAX is also adjusted in a similar way.

Fixes: 715c5ce454a6 ("libbpf: Add low level TC-BPF management API")
Cc: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
  tools/lib/bpf/netlink.c | 23 +++++++++++++++++++++++
  1 file changed, 23 insertions(+)

Changelog:
   v2 -> v3:
     - define/redefine TCA_BPF_MAX based on latest uapi header.
       this enables to remove the v2 check "TCA_BPF_MAX < TCA_BPF_ID"
       in __get_tc_info() which may cause -EOPNOTSUPP error
       if the library is compiled in old system and used in
       newer system.
   v1 -> v2:
     - gcc 8.3 doesn't like macro condition
         (__TCA_BPF_MAX - 1) <= 10
       where __TCA_BPF_MAX is an enumerator value.
       So define TCA_BPF_ID macro without macro condition.

diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 39f25e09b51e..37cb6b50f4b3 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -22,6 +22,29 @@
  #define SOL_NETLINK 270
  #endif
+#ifndef TC_H_CLSACT
+#define TC_H_CLSACT TC_H_INGRESS
+#endif
+
+#ifndef TC_H_MIN_INGRESS
+#define TC_H_MIN_INGRESS 0xFFF2U
+#endif
+
+#ifndef TC_H_MIN_EGRESS
+#define TC_H_MIN_EGRESS 0xFFF3U
+#endif
+
+/* TCA_BPF_ID is an enumerator value in uapi/linux/pkt_cls.h.
+ * Declare it as a macro here so old system can still work
+ * without TCA_BPF_ID defined in pkt_cls.h.
+ */
+#define TCA_BPF_ID 11
+
+#ifdef TCA_BPF_MAX
+#undef TCA_BPF_MAX
+#endif
+#define TCA_BPF_MAX 11
+
  typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);   typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,


See 49a249c38726 ("tools/bpftool: copy a few net uapi headers to tools directory"). If this is not included from tools/lib/bpf/ then it would need fixing from Makefile
side.

Thanks, Daniel. Yes, the pkt_cls.h and pkt_sched.h are in kernel tools/include/uapi/linux directory. But these two files are not
in libbpf repo and hence system header files are used.

I will submit a patch to libbpf to fix the issue.


Thanks,
Daniel



[Index of Archives]     [Linux Samsung SoC]     [Linux Rockchip SoC]     [Linux Actions SoC]     [Linux for Synopsys ARC Processors]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]


  Powered by Linux