add script to test max MTU

README.md

@@ -79,13 +79,11 @@ This setup is currently only adapted for Niri.
 
 ## Wallpaper & Colortheme
 
-The most suitable primary color (or so-called flavor) will be chosen from the [Catppuccin Mocha](https://catppuccin.com/palette/) palette and applied to various apps automatically after changing wallpaper. See also:
-
 - [wallpaper-carousel](https://github.com/Uyanide/Wallpaper_Carousel): an Image Carousel implemented with Qt Widgets to browse and set wallpapers from.
 - [wallpaper-daemon](./config/scripts/.local/scripts/wallpaper-daemon): automatic blur (only works in niri).
 - [change-wallpaper](./config/scripts/.local/scripts/change-wallpaper): script that changes wallpaper with a few extra features.
-- [change-colortheme](./config/scripts/.local/scripts/change-colortheme): script that changes color scheme based on wallpaper.
-- [backgrounds collection](https://github.com/Uyanide/backgrounds) for personal use.
+- [change-colortheme](./config/scripts/.local/scripts/change-colortheme): script that extract colors from the current wallpaper and generate a catppuccin color scheme accordingly.
+- [backgrounds](https://github.com/Uyanide/backgrounds) collection for personal use (mostly waifus).
 
 ## Rofi
 

backgrounds

@@ -0,0 +1 @@
+config/wallpaper/Pictures/backgrounds

config/scripts/.local/scripts/mtu-test

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+
+import sys
+import subprocess
+
+
+def ping(host, packet_size, is_ipv6=False):
+    if is_ipv6:
+        header_size = 48  # 40 bytes IPv6 header + 8 bytes ICMPv6 header
+        cmd = ['ping', '-6', '-c', '2', '-M', 'do', '-s', str(packet_size - header_size), host]
+    else:
+        header_size = 28  # 20 bytes IP header + 8 bytes ICMP header
+        cmd = ['ping', '-4', '-c', '2', '-M', 'do', '-s', str(packet_size - header_size), host]
+
+    try:
+        result = subprocess.run(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        return result.returncode == 0
+    except Exception:
+        return False
+
+
+def bin_search_mtu(host, min_mtu, max_mtu, is_ipv6=False):
+    l = min_mtu
+    h = max_mtu
+    ret = 0
+
+    print(f"Testing {'IPv6' if is_ipv6 else 'IPv4'} MTU for {host}...")
+
+    if not ping(host, l, is_ipv6):
+        print(f"  Cannot reach host even with MTU {l}.")
+        return None
+
+    while l <= h:
+        m = (l + h) // 2
+        if ping(host, m, is_ipv6):
+            ret = m
+            print(f"  MTU {m} OK")
+            l = m + 1
+        else:
+            print(f"  MTU {m} Failed")
+            h = m - 1
+
+    return ret
+
+
+def main():
+    if len(sys.argv) < 2 or len(sys.argv) == 3 or len(sys.argv) > 4:
+        print(f"Usage: {sys.argv[0]} <domain> [min_mtu max_mtu]")
+        sys.exit(1)
+
+    domain = sys.argv[1]
+    min_search = sys.argv[2] if len(sys.argv) >= 4 else 1000
+    max_search = sys.argv[3] if len(sys.argv) >= 4 else 1500
+
+    ipv4_mtu = bin_search_mtu(domain, min_search, max_search, is_ipv6=False)
+    if ipv4_mtu:
+        print(f"Max IPv4 MTU: {ipv4_mtu}")
+    else:
+        print("Could not determine IPv4 MTU.")
+
+    print("-" * 20)
+
+    ipv6_mtu = bin_search_mtu(domain, min_search, max_search, is_ipv6=True)
+    if ipv6_mtu:
+        print(f"Max IPv6 MTU: {ipv6_mtu}")
+    else:
+        print("Could not determine IPv6 MTU.")
+
+
+if __name__ == "__main__":
+    main()

memo/fontconfig.md

@@ -1,22 +1,20 @@
 ### Font packages (involved in fontconfig)
 
-- ttf-sarasa-gothi
-- ttf-symbola (AUR)
-- noto-fonts
-- noto-fonts-cjk
-- noto-fonts-emoji
-- ttf-nerd-fonts-symbols
-- maplemono-nf-cn (AUR)
+- `extra/ttf-sarasa-gothic`
+- `aur/ttf-symbola`
+- `extra/noto-fonts`
+- `extra/noto-fonts-cjk`
+- `extra/noto-fonts-emoji`
+- `extra/ttf-nerd-fonts-symbols`
+- `aur/maplemono-nf-cn`
 
 ### Other fonts (used but not involved in fontconfig)
 
-- Sour Gummy
-- Font Awesome 6 Free
-- Meslo LGM Nerd Font Mono
+- Sour Gummy (from [Google Fonts](https://fonts.google.com/specimen/Sour+Gummy))
+- Font Awesome 6 Free (extracted from an AUR package which no longer exists)
+- `extra/ttf-meslo-nerd`
 
-### Fontconfig configuration
-
-> `~/.config/fontconfig/fonts.conf`
+### Font configuration
 
 ```xml
 <?xml version='1.0'?>
@@ -82,3 +80,9 @@
   </alias>
 </fontconfig>
 ```
+
+### Notes
+
+- `~/.fonts/` is deprecated, use `~/.local/share/fonts/` instead.
+
+- `~/.config/fontconfig/fonts.conf` will be loaded by `/etc/fonts/conf.d/50-user.conf` and therefore takes precedence over the rules defined in files starting with a higher number.