Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-06 Thread Hannes Frederic Sowa
On 05.12.2016 17:54, Edward Cree wrote: > On 05/12/16 16:50, Hannes Frederic Sowa wrote: >> On 05.12.2016 17:40, Edward Cree wrote: >>> I may be completely mistaken here, but can't the verifier unroll the loop >>> 'for >>> verification' without it actually being unrolled in the program? >>> I.e.,

Re: [flamebait] xdp Was: Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-05 Thread Alexei Starovoitov
On Mon, Dec 05, 2016 at 09:08:36PM -0800, Tom Herbert wrote: > On Mon, Dec 5, 2016 at 7:05 PM, Alexei Starovoitov > wrote: > > On Sun, Dec 04, 2016 at 05:05:28PM +0100, Hannes Frederic Sowa wrote: > >> > >> If one of those eBPF verifiers only accepts a certain number

Re: [flamebait] xdp Was: Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-05 Thread Tom Herbert
On Mon, Dec 5, 2016 at 7:05 PM, Alexei Starovoitov wrote: > On Sun, Dec 04, 2016 at 05:05:28PM +0100, Hannes Frederic Sowa wrote: >> >> If one of those eBPF verifiers only accepts a certain number of INSN, as >> fundamental as backwards jumps, we might end up with

Re: [flamebait] xdp Was: Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-05 Thread Alexei Starovoitov
On Sun, Dec 04, 2016 at 05:05:28PM +0100, Hannes Frederic Sowa wrote: > > If one of those eBPF verifiers only accepts a certain number of INSN, as > fundamental as backwards jumps, we might end up with two compiler? two compilers? We already have five. There is gcc bpf backend (unmaintained) and

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-05 Thread Edward Cree
On 05/12/16 16:50, Hannes Frederic Sowa wrote: > On 05.12.2016 17:40, Edward Cree wrote: >> I may be completely mistaken here, but can't the verifier unroll the loop >> 'for >> verification' without it actually being unrolled in the program? >> I.e., any "proof that the loop terminates" should

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-05 Thread Hannes Frederic Sowa
On 05.12.2016 17:40, Edward Cree wrote: > On 02/12/16 19:25, Hannes Frederic Sowa wrote: >> On 02.12.2016 19:39, Alexei Starovoitov wrote: >>> Hannes, >>> Not too long ago you proposed a very interesting idea to add >>> support for bounded loops without adding any new bpf instructions and >>>

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-05 Thread Edward Cree
On 02/12/16 19:25, Hannes Frederic Sowa wrote: > On 02.12.2016 19:39, Alexei Starovoitov wrote: >> Hannes, >> Not too long ago you proposed a very interesting idea to add >> support for bounded loops without adding any new bpf instructions and >> changing llvm (which was way better than my 'rep'

Re: [flamebait] xdp Was: Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-04 Thread Hannes Frederic Sowa
Hello, On 03.12.2016 00:34, Alexei Starovoitov wrote: > On Fri, Dec 02, 2016 at 08:42:41PM +0100, Hannes Frederic Sowa wrote: >> On Fri, Dec 2, 2016, at 20:25, Hannes Frederic Sowa wrote: >>> On 02.12.2016 19:39, Alexei Starovoitov wrote: On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-03 Thread Sargun Dhillon
On Fri, Dec 2, 2016 at 4:20 PM, Alexei Starovoitov wrote: > On Fri, Dec 02, 2016 at 11:42:15AM -0800, John Fastabend wrote: >> >> As far as pattern search for DNS packets... >> >> it was requested by Cloudflare guys back in March: >> >>

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread Alexei Starovoitov
On Fri, Dec 02, 2016 at 11:42:15AM -0800, John Fastabend wrote: > >> As far as pattern search for DNS packets... > >> it was requested by Cloudflare guys back in March: > >> https://github.com/iovisor/bcc/issues/471 > >> and it is useful for several tracing use cases as well. > >> Unfortunately no

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread Alexei Starovoitov
On Fri, Dec 02, 2016 at 08:42:41PM +0100, Hannes Frederic Sowa wrote: > On Fri, Dec 2, 2016, at 20:25, Hannes Frederic Sowa wrote: > > On 02.12.2016 19:39, Alexei Starovoitov wrote: > > > On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes Frederic Sowa wrote: > > >> like") and the problematic of

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread Hannes Frederic Sowa
On Fri, Dec 2, 2016, at 20:42, John Fastabend wrote: > On 16-12-02 11:25 AM, Hannes Frederic Sowa wrote: > > Hi, > > > > On 02.12.2016 19:39, Alexei Starovoitov wrote: > >> On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes Frederic Sowa wrote: > >>> like") and the problematic of parsing DNS

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread Hannes Frederic Sowa
On Fri, Dec 2, 2016, at 20:25, Hannes Frederic Sowa wrote: > On 02.12.2016 19:39, Alexei Starovoitov wrote: > > On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes Frederic Sowa wrote: > >> like") and the problematic of parsing DNS packets in XDP due to string > >> processing and looping inside eBPF.

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread John Fastabend
On 16-12-02 11:25 AM, Hannes Frederic Sowa wrote: > Hi, > > On 02.12.2016 19:39, Alexei Starovoitov wrote: >> On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes Frederic Sowa wrote: >>> like") and the problematic of parsing DNS packets in XDP due to string >>> processing and looping inside eBPF. >>

Re: bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread Hannes Frederic Sowa
Hi, On 02.12.2016 19:39, Alexei Starovoitov wrote: > On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes Frederic Sowa wrote: >> like") and the problematic of parsing DNS packets in XDP due to string >> processing and looping inside eBPF. > > Hannes, > Not too long ago you proposed a very

bpf bounded loops. Was: [flamebait] xdp

2016-12-02 Thread Alexei Starovoitov
On Thu, Dec 01, 2016 at 10:27:12PM +0100, Hannes Frederic Sowa wrote: > like") and the problematic of parsing DNS packets in XDP due to string > processing and looping inside eBPF. Hannes, Not too long ago you proposed a very interesting idea to add support for bounded loops without adding any