[RESEND PATCH v3 7/9] net/tcp: simplify tcp header filling code

[Simon Glass]

Hi Mikhail,

On Fri, 23 Aug 2024 at 09:12, Mikhail Kshevetskiy
<mikhail.kshevetskiy at genexis.eu> wrote:
>
> By the way, I'd like to know your opinion:
>  * should I add a sample implementation of http/1.1 compatible
> web-server to this patch series?
>
> This can be used as a base for other implementations like firmware
> upgrade web-server used by some vendors.

Do you mean using the sandbox emulator? Yes I think that would be very helpful.

Regards,
Simon


>
> Mikhail Kshevetskiy
>
>
> On 17.08.2024 18:58, Simon Glass wrote:
> > Hi Mikhail,
> >
> > On Wed, 14 Aug 2024 at 04:32, Mikhail Kshevetskiy
> > <mikhail.kshevetskiy at iopsys.eu> wrote:
> >> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> >> ---
> >>  net/tcp.c | 70 +++++++++++++++++++++++++++++--------------------------
> >>  1 file changed, 37 insertions(+), 33 deletions(-)
> >>
> > Reviewed-by: Simon Glass <sjg at chromium.org>
> >
> > nits below
> >
> >> diff --git a/net/tcp.c b/net/tcp.c
> >> index 2c34556c26d..7014d5b4f43 100644
> >> --- a/net/tcp.c
> >> +++ b/net/tcp.c
> >> @@ -527,10 +527,37 @@ void net_set_syn_options(struct tcp_stream *tcp, union tcp_build_pkt *b)
> >>         b->ip.end = TCP_O_END;
> >>  }
> >>
> >> +const char *tcpflags_to_str(char tcpflags, char *buf, int size)
> >> +{
> >> +       int i = 0, len;
> >> +       char *orig = buf;
> >> +       const struct {
> >> +               int             bit;
> >> +               const char      *name;
> >> +       } desc[] = {{TCP_RST, "RST"}, {TCP_SYN, "SYN"}, {TCP_PUSH, "PSH"},
> >> +                   {TCP_FIN, "FIN"}, {TCP_ACK, "ACK"}, {0, NULL}};
> >> +
> >> +       *orig = '\0';
> >> +       while (desc[i].name != NULL) {
> > try to avoid comparing with NULL or 0
> >
> >> +               len = strlen(desc[i].name);
> >> +               if (size <= len + 1)
> >> +                       break;
> >> +               if (buf != orig) {
> >> +                       *buf++ = ',';
> >> +                       size--;
> >> +               }
> >> +               strcpy(buf, desc[i].name);
> >> +               buf += len;
> >> +               size -= len;
> >> +       }
> >> +       return orig;
> >> +}
> >> +
> >>  int tcp_set_tcp_header(struct tcp_stream *tcp, uchar *pkt, int payload_len,
> >>                        u8 action, u32 tcp_seq_num, u32 tcp_ack_num)
> >>  {
> >>         union tcp_build_pkt *b = (union tcp_build_pkt *)pkt;
> >> +       char buf[24];
> >>         int pkt_hdr_len;
> >>         int pkt_len;
> >>         int tcp_len;
> >> @@ -540,55 +567,32 @@ int tcp_set_tcp_header(struct tcp_stream *tcp, uchar *pkt, int payload_len,
> >>          *         4 bits reserved options
> >>          */
> >>         b->ip.hdr.tcp_flags = action;
> >> -       pkt_hdr_len = IP_TCP_HDR_SIZE;
> >>         b->ip.hdr.tcp_hlen = SHIFT_TO_TCPHDRLEN_FIELD(LEN_B_TO_DW(TCP_HDR_SIZE));
> >>
> >>         switch (action) {
> >>         case TCP_SYN:
> >>                 debug_cond(DEBUG_DEV_PKT,
> >> -                          "TCP Hdr:SYN (%pI4, %pI4, sq=%u, ak=%u)\n",
> >> -                          &tcp->rhost, &net_ip,
> >> -                          tcp_seq_num, tcp_ack_num);
> >> +                          "TCP Hdr:%s (%pI4, %pI4, s=%u, a=%u)\n",
> >> +                          tcpflags_to_str(action, buf, sizeof(buf)),
> >> +                          &tcp->rhost, &net_ip, tcp_seq_num, tcp_ack_num);
> >>                 net_set_syn_options(tcp, b);
> >>                 pkt_hdr_len = IP_TCP_O_SIZE;
> >>                 break;
> >> -       case TCP_SYN | TCP_ACK:
> >> -       case TCP_ACK:
> >> -               pkt_hdr_len = IP_HDR_SIZE + net_set_ack_options(tcp, b);
> >> -               b->ip.hdr.tcp_flags = action;
> >> -               debug_cond(DEBUG_DEV_PKT,
> >> -                          "TCP Hdr:ACK (%pI4, %pI4, s=%u, a=%u, A=%x)\n",
> >> -                          &tcp->rhost, &net_ip, tcp_seq_num, tcp_ack_num,
> >> -                          action);
> >> -               break;
> >> -       case TCP_FIN:
> >> -               debug_cond(DEBUG_DEV_PKT,
> >> -                          "TCP Hdr:FIN  (%pI4, %pI4, s=%u, a=%u)\n",
> >> -                          &tcp->rhost, &net_ip, tcp_seq_num, tcp_ack_num);
> >> -               payload_len = 0;
> >> -               pkt_hdr_len = IP_TCP_HDR_SIZE;
> >> -               break;
> >>         case TCP_RST | TCP_ACK:
> >>         case TCP_RST:
> >>                 debug_cond(DEBUG_DEV_PKT,
> >> -                          "TCP Hdr:RST  (%pI4, %pI4, s=%u, a=%u)\n",
> >> +                          "TCP Hdr:%s (%pI4, %pI4, s=%u, a=%u)\n",
> >> +                          tcpflags_to_str(action, buf, sizeof(buf)),
> >>                            &tcp->rhost, &net_ip, tcp_seq_num, tcp_ack_num);
> >> +               pkt_hdr_len = IP_TCP_HDR_SIZE;
> >>                 break;
> >> -       /* Notify connection closing */
> >> -       case (TCP_FIN | TCP_ACK):
> >> -       case (TCP_FIN | TCP_ACK | TCP_PUSH):
> >> -               debug_cond(DEBUG_DEV_PKT,
> >> -                          "TCP Hdr:FIN ACK PSH(%pI4, %pI4, s=%u, a=%u, A=%x)\n",
> >> -                          &tcp->rhost, &net_ip,
> >> -                          tcp_seq_num, tcp_ack_num, action);
> >> -               fallthrough;
> >>         default:
> >>                 pkt_hdr_len = IP_HDR_SIZE + net_set_ack_options(tcp, b);
> >> -               b->ip.hdr.tcp_flags = action | TCP_PUSH | TCP_ACK;
> >>                 debug_cond(DEBUG_DEV_PKT,
> >> -                          "TCP Hdr:dft  (%pI4, %pI4, s=%u, a=%u, A=%x)\n",
> >> -                          &tcp->rhost, &net_ip,
> >> -                          tcp_seq_num, tcp_ack_num, action);
> >> +                          "TCP Hdr:%s (%pI4, %pI4, s=%u, a=%u)\n",
> >> +                          tcpflags_to_str(action, buf, sizeof(buf)),
> >> +                          &tcp->rhost, &net_ip, tcp_seq_num, tcp_ack_num);
> >> +               break;
> >>         }
> >>
> >>         pkt_len = pkt_hdr_len + payload_len;
> >> --
> >> 2.39.2
> >>
> > Regards,
> > Simon