On 4/18/2024 12:06 PM, Willem de Bruijn wrote: > Abhishek Chauhan wrote: >> tstamp_type is now set based on actual clockid_t compressed >> into 2 bits. >> >> To make the design scalable for future needs this commit bring in >> the change to extend the tstamp_type:1 to tstamp_type:2 to support >> other clockid_t timestamp. >> >> We now support CLOCK_TAI as part of tstamp_type as part of this >> commit with exisiting support CLOCK_MONOTONIC and CLOCK_REALTIME. >> >> Link: https://lore.kernel.org/netdev/bc037db4-58bb-4861-ac31-a361a93841d3@xxxxxxxxx/ >> Signed-off-by: Abhishek Chauhan <quic_abchauha@xxxxxxxxxxx> >> >> /** >> - * tstamp_type:1 can take 2 values each >> + * tstamp_type:2 can take 4 values each >> * represented by time base in skb >> * 0x0 => real timestamp_type >> * 0x1 => mono timestamp_type >> + * 0x2 => tai timestamp_type >> + * 0x3 => undefined timestamp_type > > Same point as previous patch about comment that repeats name. > Will take care, Noted! >> @@ -833,7 +836,8 @@ enum skb_tstamp_type { >> * @tstamp_type: When set, skb->tstamp has the >> * delivery_time in mono clock base (i.e. EDT). Otherwise, the >> * skb->tstamp has the (rcv) timestamp at ingress and >> - * delivery_time at egress. >> + * delivery_time at egress or skb->tstamp defined by skb->sk->sk_clockid >> + * coming from userspace > > I would simplify the comment: clock base of skb->tstamp. > Already in the first patch. > Will take care, Noted! >> * @napi_id: id of the NAPI struct this skb came from >> * @sender_cpu: (aka @napi_id) source CPU in XPS >> * @alloc_cpu: CPU which did the skb allocation. >> @@ -961,7 +965,7 @@ struct sk_buff { >> /* private: */ >> __u8 __mono_tc_offset[0]; >> /* public: */ >> - __u8 tstamp_type:1; /* See SKB_CLOCK_*_MASK */ >> + __u8 tstamp_type:2; /* See skb_tstamp_type enum */ > > Probably good to call out that according to pahole this fills a hole. > I will do that . >> #ifdef CONFIG_NET_XGRESS >> __u8 tc_at_ingress:1; /* See TC_AT_INGRESS_MASK */ >> __u8 tc_skip_classify:1; >> @@ -1096,10 +1100,12 @@ struct sk_buff { >> */ >> #ifdef __BIG_ENDIAN_BITFIELD >> #define SKB_MONO_DELIVERY_TIME_MASK (1 << 7) >> -#define TC_AT_INGRESS_MASK (1 << 6) >> +#define SKB_TAI_DELIVERY_TIME_MASK (1 << 6) > > SKB_TSTAMP_TYPE_BIT2_MASK? > I was thinking to keep it as TAI because it will confuse developers. I hope thats okay. >> +#define TC_AT_INGRESS_MASK (1 << 5) >> #else >> #define SKB_MONO_DELIVERY_TIME_MASK (1 << 0) >> -#define TC_AT_INGRESS_MASK (1 << 1) >> +#define SKB_TAI_DELIVERY_TIME_MASK (1 << 1) >> +#define TC_AT_INGRESS_MASK (1 << 2) >> #endif >> #define SKB_BF_MONO_TC_OFFSET offsetof(struct sk_buff, __mono_tc_offset) >> >> @@ -4206,6 +4212,11 @@ static inline void skb_set_delivery_time(struct sk_buff *skb, ktime_t kt, >> case CLOCK_MONOTONIC: >> skb->tstamp_type = SKB_CLOCK_MONO; >> break; >> + case CLOCK_TAI: >> + skb->tstamp_type = SKB_CLOCK_TAI; >> + break; >> + default: >> + WARN_ONCE(true, "clockid %d not supported", tstamp_type); > > and set to 0 and default tstamp_type? > Actually thinking about it. I feel if its unsupported just fall back to default is the correct thing. I will take care of this. >> } >> } > >> > > @@ -9372,10 +9378,16 @@ static struct bpf_insn *bpf_convert_tstamp_type_read(const struct bpf_insn *si, >> *insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, >> SKB_BF_MONO_TC_OFFSET); >> *insn++ = BPF_JMP32_IMM(BPF_JSET, tmp_reg, >> - SKB_MONO_DELIVERY_TIME_MASK, 2); >> + SKB_MONO_DELIVERY_TIME_MASK | SKB_TAI_DELIVERY_TIME_MASK, 2); >> + *insn++ = BPF_JMP32_IMM(BPF_JSET, tmp_reg, >> + SKB_MONO_DELIVERY_TIME_MASK, 3); >> + *insn++ = BPF_JMP32_IMM(BPF_JSET, tmp_reg, >> + SKB_TAI_DELIVERY_TIME_MASK, 4); >> *insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_TSTAMP_UNSPEC); >> *insn++ = BPF_JMP_A(1); >> *insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_TSTAMP_DELIVERY_MONO); >> + *insn++ = BPF_JMP_A(1); >> + *insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_TSTAMP_DELIVERY_TAI); >> >> return insn; >> } >> @@ -9418,10 +9430,26 @@ static struct bpf_insn *bpf_convert_tstamp_read(const struct bpf_prog *prog, >> __u8 tmp_reg = BPF_REG_AX; >> >> *insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, SKB_BF_MONO_TC_OFFSET); >> + /*check if all three bits are set*/ >> *insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, >> - TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK); >> - *insn++ = BPF_JMP32_IMM(BPF_JNE, tmp_reg, >> - TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK, 2); >> + TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK | >> + SKB_TAI_DELIVERY_TIME_MASK); >> + /*if all 3 bits are set jump 3 instructions and clear the register */ >> + *insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, >> + TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK | >> + SKB_TAI_DELIVERY_TIME_MASK, 4); >> + /*Now check Mono is set with ingress mask if so clear */ >> + *insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, >> + TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK, 3); >> + /*Now Check tai is set with ingress mask if so clear */ >> + *insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, >> + TC_AT_INGRESS_MASK | SKB_TAI_DELIVERY_TIME_MASK, 2); >> + /*Now Check tai and mono are set if so clear */ >> + *insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, >> + SKB_MONO_DELIVERY_TIME_MASK | >> + SKB_TAI_DELIVERY_TIME_MASK, 1); > > This looks as if all JEQ result in "if so clear"? > > Is the goal to only do something different for the two bits being 0x1, > can we have a single test with a two-bit mask, rather than four tests? > I think Martin wanted to take care of TAI as well. I will wait for his comment here My Goal was to take care of invalid combos which does not hold valid 1. If all 3 bits are set => invalid combo (Test case written is Insane) 2. If 2 bits are set (tai+mono)(Test case written is Insane) => this cannot happen (because clock base can only be one in skb) 3. If 2 bit are set (ingress + tai/mono) => This is existing logic + tai being added (clear tstamp in ingress) 4. For all other cases go ahead and fill in the tstamp in the dest register. >
