This patch is to simplify the uapi bpf.h regarding to the tstamp type and use a similar way as the kernel to describe the value stored in __sk_buff->tstamp. My earlier thought was to avoid describing the semantic and clock base for the rcv timestamp until there is more clarity on the use case, so the __sk_buff->delivery_time_type naming instead of __sk_buff->tstamp_type. With some thoughts, it can reuse the UNSPEC naming. This patch first removes BPF_SKB_DELIVERY_TIME_NONE and also rename BPF_SKB_DELIVERY_TIME_UNSPEC to BPF_SKB_TSTAMP_UNSPEC and BPF_SKB_DELIVERY_TIME_MONO to BPF_SKB_TSTAMP_DELIVERY_MONO. The semantic of BPF_SKB_TSTAMP_DELIVERY_MONO is the same: __sk_buff->tstamp has delivery time in mono clock base. BPF_SKB_TSTAMP_UNSPEC means __sk_buff->tstamp has the (rcv) tstamp at ingress and the delivery time at egress. At egress, the clock base could be found from skb->sk->sk_clockid. __sk_buff->tstamp == 0 naturally means NONE, so NONE is not needed. With BPF_SKB_TSTAMP_UNSPEC for the rcv tstamp at ingress, the __sk_buff->delivery_time_type is also renamed to __sk_buff->tstamp_type which was also suggested in the earlier discussion: https://lore.kernel.org/bpf/b181acbe-caf8-502d-4b7b-7d96b9fc5d55@iogearbox.net/ The above will then make __sk_buff->tstamp and __sk_buff->tstamp_type the same as its kernel skb->tstamp and skb->mono_delivery_time counter part. The internal kernel function bpf_skb_convert_dtime_type_read() is then renamed to bpf_skb_convert_tstamp_type_read() and it can be simplified with the BPF_SKB_DELIVERY_TIME_NONE gone. A BPF_ALU32_IMM(BPF_AND) insn is also saved by using BPF_JMP32_IMM(BPF_JSET). The bpf helper bpf_skb_set_delivery_time() is also renamed to bpf_skb_set_tstamp(). The arg name is changed from dtime to tstamp also. It only allows setting tstamp 0 for BPF_SKB_TSTAMP_UNSPEC and it could be relaxed later if there is use case to change mono delivery time to non mono. prog->delivery_time_access is also renamed to prog->tstamp_type_access.
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| @@ -5090,23 +5090,22 @@ union bpf_attr { · 5089 unmodified lines | ||
| 5090 | 5090 | * 0 on success, or a negative error in case of failure. On error |
| 5091 | 5091 | * *dst* buffer is zeroed out. |
| 5092 | 5092 | * |
| 5093 | − * long bpf_skb_set_delivery_time(struct sk_buff *skb, u64 dtime, u32 dtime_type) | |
| 5093 | + * long bpf_skb_set_tstamp(struct sk_buff *skb, u64 tstamp, u32 tstamp_type) | |
| 5094 | 5094 | * Description |
| 5095 | − * Set a *dtime* (delivery time) to the __sk_buff->tstamp and also | |
| 5096 | − * change the __sk_buff->delivery_time_type to *dtime_type*. | |
| 5095 | + * Change the __sk_buff->tstamp_type to *tstamp_type* | |
| 5096 | + * and set *tstamp* to the __sk_buff->tstamp together. | |
| 5097 | 5097 | * |
| 5098 | − * When setting a delivery time (non zero *dtime*) to | |
| 5099 | − * __sk_buff->tstamp, only BPF_SKB_DELIVERY_TIME_MONO *dtime_type* | |
| 5100 | − * is supported. It is the only delivery_time_type that will be | |
| 5101 | − * kept after bpf_redirect_*(). | |
| 5102 | − * | |
| 5103 | − * If there is no need to change the __sk_buff->delivery_time_type, | |
| 5104 | − * the delivery time can be directly written to __sk_buff->tstamp | |
| 5098 | + * If there is no need to change the __sk_buff->tstamp_type, | |
| 5099 | + * the tstamp value can be directly written to __sk_buff->tstamp | |
| 5105 | 5100 | * instead. |
| 5106 | 5101 | * |
| 5107 | − * *dtime* 0 and *dtime_type* BPF_SKB_DELIVERY_TIME_NONE | |
| 5108 | − * can be used to clear any delivery time stored in | |
| 5109 | − * __sk_buff->tstamp. | |
| 5102 | + * BPF_SKB_TSTAMP_DELIVERY_MONO is the only tstamp that | |
| 5103 | + * will be kept during bpf_redirect_*(). A non zero | |
| 5104 | + * *tstamp* must be used with the BPF_SKB_TSTAMP_DELIVERY_MONO | |
| 5105 | + * *tstamp_type*. | |
| 5106 | + * | |
| 5107 | + * A BPF_SKB_TSTAMP_UNSPEC *tstamp_type* can only be used | |
| 5108 | + * with a zero *tstamp*. | |
| 5110 | 5109 | * |
| 5111 | 5110 | * Only IPv4 and IPv6 skb->protocol are supported. |
| 5112 | 5111 | * |
| @@ -5119,7 +5118,7 @@ union bpf_attr { · 6 unmodified lines | ||
| 5119 | 5118 | * Return |
| 5120 | 5119 | * 0 on success. |
| 5121 | 5120 | * **-EINVAL** for invalid input |
| 5122 | − * **-EOPNOTSUPP** for unsupported delivery_time_type and protocol | |
| 5121 | + * **-EOPNOTSUPP** for unsupported protocol | |
| 5123 | 5122 | */ |
| 5124 | 5123 | #define __BPF_FUNC_MAPPER(FN) \ |
| 5125 | 5124 | FN(unspec), \ |
| @@ -5314,7 +5313,7 @@ union bpf_attr { · 188 unmodified lines | ||
| 5314 | 5313 | FN(xdp_load_bytes), \ |
| 5315 | 5314 | FN(xdp_store_bytes), \ |
| 5316 | 5315 | FN(copy_from_user_task), \ |
| 5317 | − FN(skb_set_delivery_time), \ | |
| 5316 | + FN(skb_set_tstamp), \ | |
| 5318 | 5317 | /* */ |
| 5319 | 5318 | |
| 5320 | 5319 | /* integer value in 'imm' field of BPF_CALL instruction selects which helper |
| @@ -5505,9 +5504,12 @@ union { \ · 184 unmodified lines | ||
| 5505 | 5504 | } __attribute__((aligned(8))) |
| 5506 | 5505 | |
| 5507 | 5506 | enum { |
| 5508 | − BPF_SKB_DELIVERY_TIME_NONE, | |
| 5509 | − BPF_SKB_DELIVERY_TIME_UNSPEC, | |
| 5510 | − BPF_SKB_DELIVERY_TIME_MONO, | |
| 5507 | + BPF_SKB_TSTAMP_UNSPEC, | |
| 5508 | + BPF_SKB_TSTAMP_DELIVERY_MONO, /* tstamp has mono delivery time */ | |
| 5509 | + /* For any BPF_SKB_TSTAMP_* that the bpf prog cannot handle, | |
| 5510 | + * the bpf prog should handle it like BPF_SKB_TSTAMP_UNSPEC | |
| 5511 | + * and try to deduce it by ingress, egress or skb->sk->sk_clockid. | |
| 5512 | + */ | |
| 5511 | 5513 | }; |
| 5512 | 5514 | |
| 5513 | 5515 | /* user accessible mirror of in-kernel sk_buff. |
| @@ -5550,7 +5552,7 @@ struct __sk_buff { · 36 unmodified lines | ||
| 5550 | 5552 | __u32 gso_segs; |
| 5551 | 5553 | __bpf_md_ptr(struct bpf_sock *, sk); |
| 5552 | 5554 | __u32 gso_size; |
| 5553 | − __u8 delivery_time_type; | |
| 5555 | + __u8 tstamp_type; | |
| 5554 | 5556 | __u32 :24; /* Padding, future use. */ |
| 5555 | 5557 | __u64 hwtstamp; |
| 5556 | 5558 | }; |