[components][net][lwip][port] Fix next-hop finding in lwip_ip4_route_src. #7504
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We should compare source IP address and netif IP address with netmask at the same time. Original implementation always return default netif to caller.
components/net/lwip/port/sys_arch.c
Outdated
| @@ -684,15 +684,15 @@ struct netif *lwip_ip4_route_src(const ip4_addr_t *dest, const ip4_addr_t *src) | |||
| /* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */ | |||
| if (src != NULL) | |||
| { | |||
| if (ip4_addr_cmp(src, netif_ip4_addr(netif))) | |||
| if (ip4_addr_netcmp(src, netif_ip4_addr(netif), netif_ip4_netmask(netif))) | |||
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在这一步的src具体是谁？根据之前的经验发现src其实就是来自某个netif的addr，所以必然会出现src==netif->addr。而在多网卡的情况下，如果存在多个子网相同的情况ip4_addr_netcmp将取决于链表中的靠前的netif网卡对象。
所以请教一下lwip_ip4_route_src的真实意图到底是什么？
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Hi,
並非某個 netif 的 IP 位址，依我的測試，我將 src, netif.ip 打印出來如下：
(1) HTTPD response時，src 是 HTTP client 的 IP Address。
(2) PING out 時，src 是 Target IP Address。
HTTPD:
PING out:
這個函式應該實作 forwarded PKT 的 next hop 是該往那個 network interface。
依原有的實作，幾乎是 Not match!! 所以總是往 default interface 傳送，導致不同網段的路由，完全失效 !!
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按我的理解是src匹配路由的规则就是相当于socket 的bind操作。
而如果没有socket的bind操作的话，其实只要在此函数的末尾不要让他返回default对象，而是返回NULl就行了。
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Agree and tested.
已修改成 route_src search 不到就回傳NULL; 後面還是有一個 search dest ip address 的 ip routing。
netdev_ping should execute with specified networking interface, not default_interface first.
wosayttn
changed the title
Return NULL if have no matching in lwip_ip4_route_src. This reverts commit 8958093.
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Thanks. |
拉取/合并请求描述：(PR description)
[
Original implementation always return default netif to caller.
We should compare source IP address and netif IP address with netmask at the same time.
Tested on multi-ethernet cards on Nuvoton platform.
]
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#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up