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

[Mikhail Kshevetskiy]

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.

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